Apple and hardware repairs

My MacBook today crashed and the only refused to start until I let it sit for a bit.

On the off-chance this isn’t one of those weird things that happens moments, at what point during the repair process, if any, do I have to pay for Apple to do diagnostics?

I know the Genius visit is free, but I don’t know what happens after I have to leave it with them.

1-year warranty? Got the extended warranty?

No. Usually the Apple shit I have fails when that runs out.

It’s OK now. After talking someone who had a similar issue, I’m not rulling out Windows via Parallels just really messing up the PMU stuff. They’ve run into a close variation of the problem.