Winter time will be approaching my area in the coming months and I need advice. I've kept my bonsai outside all spring and summer but I do not know if I should bring them inside for the winter or leave outside. I've brought trees in before and the shock of it killed them. Any advice on in home care would be great. I have a few ficuses and an azalea

Both of them do really good in 5c.

What climate do you have?

Ficus needs to be inside when it gets frosty.
Most azaleas traded are moderately to fully frost resistent.

Plants do not "die from shock when brought in", so look at your care.

It all boils down to how you take care of your plant. A weather change wouldn't be much of a problem.

The best answer is find a bonsai group in your area and follow their practice.

I bring my ficus inside when temps drop below 50F/10C. Azaleas should stay outside but may need protection against heavy drying cold wind.