My usual carry is a SIG auto so I normally carry one spare magazine but not specifically for the added ammo. ;)
ALWAYS carry! ~ NEVER tell!
I turned an old cell phone belt pouch into a carrier for an extra mag. I keep 1 in the pipe, + 10 in the grip.....then I have another 10 on my belt for backup. To answer the question, I carry one extra mag.
Victory rewards not the army that fires the most rounds, but who is the more accurate shot. ---Unknown
I carry an extra mag for my primary weapon but I don't carry an extra one for my BUG. I also keep extra ammo in my vehicle.
USAF Retired, CATM, SC CWP, NH NR CWP, NRA Life/Endowment/Patron
To preserve liberty, it is essential that the whole body of people always possess arms, and be taught alike, especially when young, how to use them... -- Richard Henry Lee, 1787
10 + 1 in the gun and 2 extra mags for 31 rds total. Usually also a 5 or 6 shot .38 revolver and a tacti-cool folder or Cold Steel Desperado.
Better to perish in the struggle for freedom than live to see defeat. There ARE things to be feared more than death. The fyrd is a Constitutional imperative.
M&P 9 with a 17 round mag and one spare 17 round on the belt. If it's hot out I'll leave the extra mag at home.
Don't hit at all if it is honorably possible to avoid hitting; but never hit soft!
-- Theodore Roosevelt --
Carry a 1911 with 7 + 1 chambered, a spare mag and a Sig 232 BUG. Always have a box of 20 cartridges in the trucks glovebox for the 1911.
Usually carry 1-2 extra mags.
One magazine. As both more rounds for the BG, and to deal with a magazine failure at a most inopportune time.
Orlando, FL
With G27 standard with mag 9 rounds with 1 in the pipe makes 10
and 1 extra mag for G23 for 13 more makes a total of 23 rounds.
Walk softly and carry a big GLOCK
Well, fact is I usually don't carry an extra mag. Just the Makarov's 8 + 1 in the chamber.
Truth is mighty and will prevail. There is nothing the matter with this, except that it ain't so.
-Mark Twain