I'm coming up on my one-whole-year smoke-free! my birthday present is a Reo, not yet sure which model.
other than batteries and a charger, what are the other things I should get?
best non-rebuildable attys? or should I use cartos? or both? how many repair kits or extra bottles and tubes?
I'm really excited and want to do it right!
Best non-rebuildable atties that I found were various 306es. You can find some on Avid Vaper. They seem to hold more juice. I did still prefer cartos -- little Smoktek 1.7's that Rob sells. If memory serves, his price on them was pretty good too.
I did buy a spare spring and a rebuild kit. Just over a year ago. They're still in the bag

I would recommend getting a spare spring, but the rebuild kit is very optional. Extra tubes are completely unnecessary.
Extra bottles really depend on the size of Reo you are getting, and your juices. If you vape any strong juices, you may want to get dedicated bottles for them. I can't get my citrus flavors out of the bottles, with any amount of washing. If you're getting a Mini, you should get a few extra spare bottles to carry extra juice with you, if you so wish. I would kind of recommend against a Mini as your first Reo. They are great, but Grand is not that much bigger, but is much more versatile.
I'd also suggest the button covers, Delrin or Brass, depending on your taste. I love their feel.
Good luck and welcome to Reoville!