"but if you've got air getting into the lines over time, you have other problems"
? who mentioned having air in the system.
New pads, new fluid, simple as.
Some do, some don't.
Ok, well new fluid was not mentioned. Just changing pads and the desire to bleed the lines, so I thought the OP was saying there was some benefit from (or need to) bleed the lines as if it were some sort of maintenance thing.
Personally I take mine to the shop every 2 years for them to flush the lines, I dont have time or patience to deal with corrosive fluids, etc.
so I just change pads when needed, but I take it in for a flush.