I haven't lost the motivation yet, despite being back to a regular schedule. I usually lose my drive when I have an unstructured day, so having to do a lot usually means I'm motivated to do even more.
I also think about my bag purchases a lot and do a ton of research (like pestering you for WIMBs, lol) as to how useful a style would be for me. I don't rehab to sell, the goal is to have a pretty purse that I can use. I'm usually pretty thrilled about my purchases and want to see them finished. If I had a bunch of rejects from a lot I bought for one specific bag, I'd probably feel 'meh' about rehabbing them too, especially if at the end of my rehab efforts I had the additional efforts of listing stuff online waiting for me, so I understand!
I do get frustrated with rehabbing when I run into the same problems over and over again. It's usually hardware tarnishing - you polish it, then dunk and have to polish again cause some of it came back, then five days later it starts getting cloudy and dull again. I highly recommend getting something with nickel hardware if you feel that way!
Lastly, I agree with what others have said. Vintage
Coach gets more and more expensive. The most gratifying rehab is when you get something cheap and make it look like you spent $500 on it at the boutique yesterday. My rehab motivation goes down when I feel like I spent too much for a mediocre outcome.