I always leave my battery in; most of the time my Mac is plugged in. I find that after about 2 years, the battery tends to fade and I need to spend about $100 on a new one. For me, it's worth it to pay that amount every couple of years for the convenience of not messing with freezers, battery removal, trying to remember whether my battery is charged, and so on. It "just works." If you can remember to keep your battery charged, I suppose removing it might save you some wear and tear. Maybe your battery will last three years instead of two.
Now think about this: If you keep your $100 in the bank for an extra year, you'll earn about $2 in interest. So really, you're talking about saving $2.
By year 4, you're going to be needing a new computer no matter what, so in either case you'll be buying a new battery -- the question is whether you buy it in year 2 or year 3.