I've had a Makita 9.6/12V for about 10 years. The batteries are
going so I bought a 14.4V Porter Cable. Love it! The Makita
rarely gets used anymore so I can save what's left of the batteries
for the 3-5/8" cut-off saw and right angle drill that take the same
battery.

You might want to check your "yellow pages" and see if someone nearby
repairs those old battery packs. They cut open the old pack and replace
the cells and cement the package back together. I have never used the
service but an In-law told me he was quite happy with the price and the
results.

It would be a shame to have to junk some useful tools because the battery
pack is getting long in the tooth.