Sticky doors

Can spray WD-40 into the door handle buttons, work them many times, and blow them out with compressed air. That should free those up. Same with the latch mechanism.

Over time the doors usually sag. You can bend them back up with a long pry bar and some 2 x 4s being careful not to bend your outer door skin or the rocker panel with the pry bar action. Do your lifting at the back edge of the door next to the quarter panel.

If you get the doors lined up properly they will not stick when you are trying to open them.

Take a check on the door hinge pins to make sure they are not totally wore out.