How many rounds, on average, to maintain your shooting skill?

i can improve with 300 rounds/week.
that's my minimum n all i can afford.

Depends what kind of skill you are trying to maintain. Long range precision shooting won't go through as many rounds as say defensive pistol shooting.

Most of my guns are just for fun, but the pistols are for self defense, so I voted minimum 100 rounds a month to maintain proficiency after first learning that gun.