The amount of line you can get on your reel depends on the diameter of the line and how big your reel is. The modern-day fishing lines are thinner and stronger than ever before meaning that it can be a long time before you ever need to replace the line on a reel.
When buying fishing line it’s only natural that the thicker the diameter, the less overall length you are going to get on a spool which is important to bear in mind if you are looking for a specific amount of fishing line. Sometimes it can be useful to have multiple lines available depending on different conditions that you are trying to fish in.
In terms of the lifespan of the line this depends on a lot of factors such as the waters that you are fishing in, the type of line that you are using and how often you fish. If you are fishing somewhere that is consistently rubbing on your line like a rocky area then this is obviously not going to last for as long as if you’re fishing in that ocean. If you are fishing in somewhere where abrasions occur then you want to check your line often.
Generally though a fishing line might last for up to three years if you are looking after it and turning it over from time to time to ensure that it is having an even amount of wear. As so often is the case, this can also come down to diameter as well as obviously the thicker a line is, the more likely that it will be able to last for a long time.