[federicotdn]

I only use C-x 1, C-x 2 and C-x 3, seems like that covers 95% of my use cases at least.

[kgwgk]

C-x 0 can also be useful.

[codr7]

Never used it, I tend to use C-x 1 to get back to one window; what's the difference?

[kgwgk]

No difference if you have two windows, but if you have three or more you just kill the current one giving the space to one of the adjacent windows.