Drick, I would not worry about the cost of changing over. Properly cared for your batteries will last you a long time. I still use original nicad's in my 9.6 volt Makita tools. I have only had one wear out and replaced it with the nimh. I have 7 battery packs, 5 chargers, 5 drills, a sander, jig saw, 2 flash lights and a grass trimmer. I know the newer tools last longer on a charge and are stronger but I can run non stop all day long with what I have. In case nobody ever told you there is a reason most cordless drills come with flash lights. Once your battery is too weak to run the drill you install it in the flash light and it will finish draining the battery fully. It is important to completely cycle the old batteries from full to dead to help maintain the cycle duration. If you follow this tip your batteries will last longer and run longer each charge. Keep an eye open for duplicates of your tools at flea markets and garage sales. Getting extra parts, batteries and chargers cheap is always worthwhile.