Upload & Sell: Off
I feel weird and not very happy about it now because I dont like spending so much time even if they book.
Why do you feel this way? Like others have said, if they do book, it sounds like you've already built a connection to them and this will only benefit the relationship. Not to say spend 3 hrs every time, but it happened, sounds like they had many questions and you delt with it, so move on - this isn't entirely a bad thing IMO.
I've probably had longer than that before. Last year I had a 3 hr round trip (drive), then we visited the venue, did a consulation / plan of sorts, looked through a couple of albums, they made me a big lunch with their family. Slightly different to you, as they'd already booked me at that point. And yeah, it took up a big chunk in a day, but it was worth it in that situation, I didn't regret / feel bad about it.
I'd say on average normal consultations are around 45mins to 90mins.
My worst consultation was getting a 3 hr train journey to London. 3 hr back. They were nice, spoke about some stuff, seemed keen. Then emailed me saying their were going with 'a friend'. That really got me down. So now I've learnt that this was just far too greater distance to travel, no matter how 'ideal' the client may be.