I bought two Makita drill/drivers in '87 and other than voluntarily replacing one chuck with keyless (so I could change drill bits more easily and use the other as a driver) and one gear (because I dropped it from about 6'), I have only changed the batteries.
BEWARE of Batteries Plus stick batteries for Makita- the OEM batteries have a thermal switch inside, which prevents overcharging and heat buildup. The one time I bought from Batteries Plus, it melted the plastic shell and fused it to the charger- they wouldn't do anything other than refund for the battery.
My other drills are 18V Milwaukee NiCd hammer drills, which I bought in 2005. I knew a design engineer at Milwaukee Electric Tool and he got me a kit with two batteries, the drill, charger and case. He had a battery from his drill, so he included that. I was drilling through a concrete wall that didn't want to be drilled through and melted the plastic around the brushes in '05 and that was covered. The carbide inserts in the chuck were damaged by me not making sure some drills were held tight and they chipped- I went to their repair center to look into a replacement and found that it was $75, so I turned to leave and saw shelves of the slightly newer version of the same drill, batteries, cases and chargers that were being clearanced after Lowe's decided to stop carrying their brand when the economy tanked. Bought another drill and the new charger and passed on the batteries ($15 each- DOH!). I have done nothing to the new hammer drill, other than use it and drop it from the top of a 12' A-frame ladder onto concrete. That bent the bit holder, but did nothing to the drill. I have bought two sets of replacement batteries and the last time, they were just the battery cells, without the shell- a lot cheaper and they work great. I use them for drilling through concrete with bits up to 1", wood with all kinds of bits including the self-feeding bits up to 2-9/16".
Power tools is an area where people can be very set in their ways.
One thing I would check into- Rigid LiIon batteries and chargers- I know a SnapOn driver who lost his garage, SnapOn truck and most of its contents, a pickup truck, the other contents of the garage and heavy smoke damage to the Alpha Romeo he inherited from his father- he had left a Rigid battery in the charger and now, he has a concrete pad to park on. I don't know anything more about it WRT the battery's age, condition, etc. Milwaukee had a recall due to similar problems, so it's possible they had a bad run. It's too bad- their tools are very good.
