How do I know if my contractor is giving me a fair deal?
Doing a soft buildout of a 2400sf retail space for an arcade my tenant wants to lease. I have estimates, but how do I know if the breakdown is reasonable?

Estimate Includes:

Electrical wiring 

HVAC

Drywall (only left side of the space, right side is exposed brick and two bathrooms, and a small storage room)

Plumbing

Carpentry

Demo

Doors and hardware (three includeing the storage room and two bathroom doors)

Polish concrete floors

Edit: We had to go back and modify the drawings, so ill be sending that to the contractors as soon as I get them. Per somosxtremos's advice, Im planning on doing a walk through with all of them so we're on the same page and to answer any questions with everyone in the same room. Thanks everyone for the help, Ill keep you posted on how it goes.

[{"id": "cweabkz", "text": "The breakdown is irrelevant.  The total cost is what matters.  Get a couple quotes and compare.", "replies": [{"id": "cwecw6o", "text": "This. Always have 3 minimum quotes. Lay it out on an excel sheet and see who's the best to go with. Contact other reputable contractors and see what their quotes are.", "replies": [{"id": "cwekdy6", "text": "Just to add to this - \"cheapest\" and \"best\" are not always the same, but if someone is way out of line with others you know someone is doing something wrong.", "replies": [], "depth": 3}], "depth": 2}, {"id": "cwelwuw", "text": "psh. fuck that.\n\nOP, talk to them about their process. ask about other examples of work they've done, with photos. ask about how they feel about the work they do. what does it mean to them? why would they be excited about this and how would they add value? make them a collaborator. \n\nyou should be inclined to pay for quality (either invested time/money) and blank cost should not be the first factor. due your pricing diligence but by no means should you just compare estimates. ", "replies": [{"id": "cwem1ra", "text": "None of that disagrees with what I said...", "replies": [], "depth": 3}], "depth": 2}, {"id": "cwet7pi", "text": "Thats what Im doing, but they breakdown numbers vary by so much, it's hard to know if the numbers are \"honest.\" For example, $8950 to paint a 100 ft wall, small office and two bathrooms...", "replies": [], "depth": 2}, {"id": "cweuzdm", "text": "I respectfully disagree. The breakdown will help you identify where the major differences in cost are.  You won't know why the costs are so different until it's too late unless you ask prior to award. For example, if you look at the bottom line only you won't know if they have included all of the scope. Say you award to the lowest bidder and his electrical number was half of what the next bidders number was... Turns out he didn't include fire alarm work, power to hvac units, assumed light fixtures would be supplied by owner etc. You can go with the \"tough you own it\" approach but that rarely works (best case you will agree to a settlement) and it will most likely delay your project schedule. Keep in mind that before the project begins you have the leverage and option to go to other contractors. Once the project starts the contractor has the leverage because it takes a lot of effort and money to change contractors in the middle of a project. The smart move is to understand exactly what you're buying before you award. You wouldn't buy a car if you were only told the company name and provided with a cost would you?  ", "replies": [], "depth": 2}], "depth": 1}, {"id": "cwed70g", "text": "Always get three quotes. Ask each contractor for cost breakdown to compare.   If they hire subcontractors,  ask them to provide the subcontractor's quote.  ", "replies": [], "depth": 1}, {"id": "cwej2w6", "text": "Very expensive buildout in Central Florida is $60+/sf.  Your use sounds like it should be around $5/sf to $18/sf, depending on existing condition of the space.", "replies": [], "depth": 1}, {"id": "cwemb7x", "text": "Ge r a detailed estimate.  Not 'fix hvac', but 'replace unit with train condenser model 12345, reroute lines, prime for use, connect ....   then rewrite, removing all pricing.  Take bid detail to other contractors and have them bid on the work.  It is the only way to get comparable  bids.", "replies": [], "depth": 1}, {"id": "cwerjtd", "text": "Ive gotten multiple quotes, the thing is they vary by quite a lot. \nFor example, one contractor's electrical is $7,000 and another contractor's electrical is $27,000....seems odd to me. None of my estimates are very detailed, ie they done cite specifics like 1000 feet of conduit priced at x amount, heat pump model 123 etc.\n", "replies": [{"id": "cwetwke", "text": "Did you send them drawings? Make sure that all bidders received the exact same scope and that the scope is clearly documented. You can create a pricing template to send to them to make leveling easier on yourself. You should also have them walk the space prior to submitting a bid to minimize unforeseen condition claims. I like to have them all walk at the same time for two reasons: 1. They may be more competitive if they see other contractors; 2. Whatever is observed or discussed on the walkthrough will be the same for everyone so their scope and understanding of the project should be consistent. There should also be an RFI (request for information) period where contractors can ask questions. Again all questions and answers should go to all bidders. Once the bids have been received you start the leveling process. You have gone through all of this effort to make sure all contractors are bidding on the same scope and this is where you check if they were paying attention. When you look at the spread for electrical there's a major discrepancy so you get them on the phone and ask them to walk you through their electrical line item. Did they assume duplex or quads at each electrical outlet. Are they all home runs (dedicated circuits)? Bx or wire in EMT? Did they include a new panel or service to the street etc. This is where you should start to see the differences in assumptions thAt make up the differences in their costs. Find out who has the most compete scope (relative to what your tenant is looking for) and go back to the other bidders and ask them to confirm or revise based on this same scope. Now you have compared apples to apples and your pricing should be in much tighter ranges. Don't forget things like logistics/storage, working hours, who pays for permits or insurance etc. You also need to consider quality and schedule. Schedule is especially important if rent doesn't start until turnover.  There is no better defense against claims then solid leveling. Get a mutual understanding and commitment before the project starts while you still have options. Once you start chances are you wont change horses mid-race so make sure you are getting what you need while still in the honeymoon phase. Document that mutual agreement as much as possible so when claims come you are prepared to remind them thAt as per their contract section 4.1 they are responsible for all temporary utility costs... Also don't ignore the unsuccessful bidders. In my experience they appreciate a follow up call explaining what they did well and where they fell short. You are coaching them to be more competitive on your next project and showing respect for their time and effort. You're also giving yourself a back up contractor in case the successful bidder falls on their face. Be wary of proposals that sound too good to be true because they usually are. You may hear some contractors say they don't bid on work or complain about your bidding being overly burdensome. Thank them for their time and move on there are plenty out there. If they won't work hard to get your business they probably will work even less to keep it. If you need contractors go to local building suppliers and ask them if they can give you some contacts with good reputations.  This is also a good financial stress test because most suppliers won't recommend contractors with high overdue balances or financial troubles. PM me if you have specific questions or want a sample leveling sheet.", "replies": [{"id": "cweyp8b", "text": "awesome advice.  \n\n", "replies": [], "depth": 3}, {"id": "cwf8dmc", "text": "Yes, great advice, thank you very much!", "replies": [], "depth": 3}], "depth": 2}], "depth": 1}, {"id": "cwh4ur7", "text": "3 quotes, compare, then negotiate as needed.", "replies": [], "depth": 1}]