Comment by snarf21

I've done a similar thing with a few past employers after I've moved on. "Hey, can you explain this code to the new person?". In some cases, I'd be glad to do a 1 hour call or whatever. They frequently ask me to submit a bill for my time and I always refuse. I don't want to turn into some kind of staff augmentation and be at their beck and call "because they are paying". Way better to think of it as a gift and I get to decide the rules.