How long do beer lines last?
Also question is, can beer line be too long?
It's easy to over do it. Too long = inadequate foam, slow pours, and too much carbonation still in solution. You should end up with two fingers of foam.
Besides, how long should my beer line be?
If you are using a direct draw setup (such as a kegerator/keg fridge) you will have to make sure you have some resistance in your system. Resistance can be created several ways but the easiest is just to increase the length of the beer line. 5mm ID beer line the length should be about 3-4.5 meters.
For most home kegerator systems, or systems with a short (<8') distance to travel: 3/16" tubing is pretty standard. If your beer will be traveling further, you may consider using a larger diameter tubing (1/4") but don't forget to keep your beer line chilled so the beer doesn't go bad or flat in the tubing.