When adjusting basis for capital gains calulcation on rental property, do improvements need to have been depreciated?

I see many comments about adjusted basis when caluculating capital gains on a rental property. What I don't find ( not in Turbo Tax and not on the IRS website) can I only use improvements that were depreciated or can I also incude improvements that totally expensed in the year they were purchased I've owned the building 30 years so lots f small things - new appliances , new hot water tank, etc