No wired doorbells in my house
 

But, both my front and side doors are needing replacing.

I was thinking of going to home depot and purchasing a standard, prehung metal door for both my front and side.
The come already prehung in the frame.
If that is the case,
I assume that would be the optimal time to wire in some doorbells or should I just go with a wireless chime and buttons?

Fishing wires in a finished home can become a lot of work. You will have to deal with insulation, blocking, other wiring & plumbing. You will need to locate a good central place for the chime, fish wires to it from both doors and then fish power wires from the transformer that operate it. I prefer wired systems myself but don't enjoy the wiring...

Yep!
Now is the time if you want wired doorbells!
I have mounted doorbell buttons on the brick molding of more doors than I can count:)

Depends on the amount of work you want. Rewiring anything can be tricky and unpredictable. I would price out some wireless doorbells, they run on batteries and aren't too bad.