Retired, collect SS and a small pension, but they have a rental property.

Their income with the net profit of the rental is far below the filing threshold, do they really need to file a return?  The gross rents would put them over the threshold, so maybe Ive answered my own question....

If they happen to sell the rental (I dont think they will) the depreciation hasn't been giving them any tax benefit (even without the depreciation they still wouldn't have any taxable income) so would it still be subject to recapture if they sell?