Door latch replacement?

My driver's side door and rear driver's side door will not stay shut. They latch moves freely up and down (and is in the "open position"). This first happened before Thanksgiving on my driver's side door. I thought I had to replace the part, but suddenly the door just closed and stayed shut after a couple of days of it being tied down (I was waiting for the part- it had to be ordered). It happened again a few weeks later and fixed itself again. Recently, my rear door on the driver's side did the same thing and it fixed itself after a couple of days. But about a week ago, both doors stopped staying closed. I have had it tied down for a week and it isn't "clicking" back into place. Do the latches need to be replaced, do you think? Or do you think something may have wiggled out of place inside the door?