"The more often — the better." Is it possible to say that?

Solution 1:

This is how I would stylize it:

"You should do this -- the more often, the better."

Other phrases that mean similar things:

You should do this as often as possible.

The more you do this, the better the results.

Results scale with use -- the more, the better

Etc.

Solution 2:

Yes, “the more often, the better” is correct.