I have as many mags as my chest rig will carry, plus one for the rifle. That means 9. Then, I have a 10-round mag for table work at the range.
I have heard people suggest that as a minimum, with the next level being double that number, for those instances when you may lose some in the field during a SHTF situation.
It is true that there is no maximum number, but we all have priorities of more guns and more ammo and only so much money.
.45acp, .40 S&W, 9mm, .38 Spl, .380 acp, 22lr
12 gauge, .223/5.56x45mm, 30-30 Winchester
2 Chron. 7:14 Christians must seek His face