1. a small hole made by a sharp object. 2. (Automotive Engineering) a perforation and loss of pressure in a pneumatic tyre, made by sharp stones, glass, etc. 3. the act of puncturing or perforating. 4. (Automotive Engineering) the act of puncturing or perforating.
The size of the bag depends on the size of the machine you have. If you have a small machine, you get a smaller bag. My machine is a 'medium' sized one, and my bag lasts approximately 6 months or so. Bags are not cheap, but they are part of the great filtration on this machine, so I suck it up (pardon the pun).
Once opened, Levemir pens and vials last a little longer than average (up to 42 days) and cloudy insulins pens, such as Novolog 70/30 and Humalog 75/25, last for a shorter time (up to 14 days). The package insert that comes with your insulin specifies how long it remains good once it is opened, or you can ask your local pharmacist.