An Easy Solution
If you have big gaps along the latch side of your doors, they were probably prehung in their frames at the factory and installed as a unit. The installer should have adjusted the frame with shims to leave about a 1/8-in. gap along the latch side, about the thickness of two quarters (coins). Sometimes the gap is far too wide.
To readjust the door frame, you have to remove the trim along the latch side to get at the shims. This job can be a hassle, especially if you have painted trim. So try this trick first. Slip a 1/16-in.-thick cardboard shim strip behind each hinge (Photos with steps 1 and 2 below). This will widen the gap along the hinge side and narrow the gap along the latch side. Hopefully, this shim will be enough to make the latch solid
1. Loosen the Hinge
Loosen the hinge screws in the jamb and insert a 1/16-in.-thick x 3/8-in.-wide piece of cardboard behind the hinge leaf. Push it against the screws and retighten them
2. Repeat for Each Shim
Follow the same procedure for each hinge. The gap along the hinge side should open about 1/16 in. and narrow the gap on the latch side.
Having more issues with your doors? Find easy fixes and solutions for your door problems here.