Bread will mold faster when it's left out at room temperature on the counter or in the pantry and even in a bread box the bread will mold faster.
The bread won't mold as fast if the bread is kept in the refrigerator but the bread can get moist and soggy when it's kept in the refrigerator so while the bread lasts longer in the refrigerator it loses some of it's quality.
Bread that you buy in stores has preservatives in it to make it last longer but even then the bread lasts at most a week or two before it goes stale and molds.
Once the bread molds the bread has become bad and should be thrown out.
Homemade bread without preservatives can mold in as little as 3 to 4 days when it's kept out on the counter.
So bread is best eaten soon after you buy it.
It's not a good idea to stock up on bread because it can mold quickly.
I buy the bread as I need it so that I don't have to worry about dealing with moldy bread.