Replacing Motor Mounts(Please Help)

I have a 93Toyota Corolla 166,000 miles. Recently started making a knocking sound when accelerating, felt like the engine was going to fall out. Took it to the mechanic, says the rear motor mount is broken and the front motor mount is cracked. Needs to be replaced. My question is should motor mounts be changed when they go bad? How bad should they get before replacing them? What harm will happen to the car if don’t get them replaced? Will it cause other damage in the car? Use car locally to drive my children around, so concerned about that. Please help if you have any advice… Thanks

If you don’t replace them the engine could fall out:)

should motor mounts be changed when they go bad?

YES…why do you think they shouldn’t be changed??? Get it fixed. With one complete broken and the other cracked…I’d bet it won’t last till thanksgiving before the engine drops and then you’re looking at a LOT MORE MONEY to fix it.

If the engine mounts are bad, they can cause misalignment between the engine and the front wheels. This will overstrss the axles and cause them to fail.

I cant replace them till this weekend because I need the car for work. I’m just concerned within that time that I will harm the car before I can get them replaced. Thanks for all the advice