Solid Hardwood, Engineered and Laminate Flooring - hardwood floor install gaps?

I have 2 questions regarding installing hardwood flooring over a plywood subfloor.
1. Should there be gaps left between the T&G boards or not? Everything I have read does not say to leave gaps, but won't this make the floor heave in humid/hot weather?
2. Is it conventional to completely remove all kitchen floor cabinets to install the flooring under them, or do you just go up to the cabinets? (the cabinets are already in place along with all plumbing and wiring).
Thanks!

Do not leave gaps between boards.
Leave expansion around edge of room and cabinets. This gap can be covered with Base and/or Quarter round.
No need to remove cabinets.

Edwin

For the technical manual on wood floor installation, go to www.installingwoodfloors.com. If all moisture and ventilation issues are addressed and wood has been allowed to acclimate (adjust) to temperature and humidity of your home before installation, and you maintain humidity levels year round at 45-55%, you should have minimal problems with expansion and contraction. Tongue & groove flooring is pulled tight when nailed with flooring nailer. An expansion gap is left along the perimeter of the room.

If you can not adjust your dishwasher to be easily removed once 3/4" flooring is installed in front of it, then you should remove the base cabinets. If dishwasher gets locked in, then you will have to remove counter if you need to pull it for repair or replacement.

thanks to both of you - your replies were both very helpful. Have a great day!