user2248: It is a known fact that you can calculate time inside a plutus validator script by looking at the txInfoValidRange attribute. Now, since this value is a range and not an exact time, it makes me wonder how large can this range be and who determines it?
This is important for me, because I might want to add a deadline of 5 days, or a deadline of 5 hours and I don't know how reliable this attribute can be.

user2537: The range is determined by the party that builds the transaction. So anybody can specify it.
A range [t1, t2] —where t1 and t2 are integers, or infinite, standing for the slot number— can include any t2 that satisfies t2 >= t1. The only additional restriction is that transactions will be dropped if t1 lies too much in the future - I think the maximum is 2 days in the future. More explanations can be found in chapter 3.3.1 here: https://plutus-pioneer-program.readthedocs.io/en/latest/pioneer/week3.html
For the smart contract validator this means that the current slot is always in the range [t1, t2] (the blockchain will make sure that the transaction will not be processed outside this range) and that this range is potentially unbounded. If your smart contract needs a smaller range, this is however no problem, it just needs to be known and followed by the one building the transaction. Your off-chain code for instance would implement this and choose a proper range needed by your validator.

2248: <p>It is a known fact that you can calculate time inside a plutus validator script by looking at the <strong>txInfoValidRang</strong>e attribute. Now, since this value is a range and not an exact time, it makes me wonder <strong>how large can this range be and who determines it?</strong></p>
<p>This is important for me, because I might want to add a deadline of 5 days, or a deadline of 5 hours and I don't know how reliable this attribute can be.</p>
 2537: <p>The range is determined by the party that builds the transaction. So anybody can specify it.</p>
<p>A range [t1, t2] —where t1 and t2 are integers, or infinite, standing for the slot number— can include any t2 that satisfies t2 &gt;= t1. The only additional restriction is that transactions will be dropped if t1 lies too much in the future - I think the maximum is 2 days in the future. More explanations can be found in chapter 3.3.1 here: <a href="https://plutus-pioneer-program.readthedocs.io/en/latest/pioneer/week3.html" rel="nofollow noreferrer">https://plutus-pioneer-program.readthedocs.io/en/latest/pioneer/week3.html</a></p>
<p>For the smart contract validator this means that the current slot is always in the range [t1, t2] (the blockchain will make sure that the transaction will not be processed outside this range) and that this range is potentially unbounded. If your smart contract needs a smaller range, this is however no problem, it just needs to be known and followed by the one building the transaction. Your off-chain code for instance would implement this and choose a proper range needed by your validator.</p>
