My earlier complaint about 99 Camry brake light coming on

Did they top it off or just bring it up a bit? I ask because if it is now full again it will overflow when the pads are replaced and the pistons are retracted back in to the calipers.

Well, it's now between the MIN MAX lines on semi-transparent reservoir. At the present rate of pad wear, it's likely to be at least 2 years before any pad changing.

A competent mechanic will check for that variable after replacing the pads.

Yes, that would be my expectation. Hopefully, it would be a "given".

A competent mechanic will remove fluid from the master cylinder before reseating the caliper pistons to remove the pads or bleed the calipers as they are reseated.

It is not necessary to reseat the caliper pistons to remove the pads, and only an INcompetent mechanic would remove fluid from the master cylinder or bleed the calipers as they are reseated. Caliper pistons are reseated when the calipers are rebuilt but since caliper rebuilds are normally done on bench on a caliper void of fluid, there is no fluid to bleed.

Caliper pistons are retracted back into the caliper so that the caliper fits over the thicker replacement pads that were installed, and it is not a good idea to open the bleed valves while doing this because there is a good chance that air will be sucked into the caliper. It would only be necessary to remove fluid from the brake fluid reservoir (not the master cylinder) if fluid was added to the reservoir prior to the brake pad replacement or if you are going to flush all of the brake fluid.