turbo,
I still have brushless motors and speed controllers from 2003 that are flying great ...... but ...... I can replace them at 1/3 the cost if they fail tomorrow.
Still, they have provided me with many $ in pleasure during the 6 years of use.
Batteries, on the other hand, ..... are quite a different matter. As you suggested, buy only what you need for the next 6 months or so. That technology
continues to improve rapidly..... and ...... you will likely be able to buy better batteries at a cheaper price only 6 months down the road. Don't get me wrong,
your batteries (if used properly and well maintained) should have a 200+ cycle life (which for me is about 2 years). They just won't be as good the 2nd year
..... and new stuff coming out will be better than your originals, so the performance gap widens quickly.
Ed