I own a few speed loaders and have some revolvers that use moon clips too but most times I wear a flat pouch from Tuff Products to hold two of their speed strips. I only wear untucked shirts. The pouch just wraps around my belt and comes in two sized depending on the caliber and number of rounds you carry.
If I think I need more than 5-6 rounds, I carry a semi auto with a spare magazine. Even if I think wrong, I still have 15 rounds on my person. I did carry speed loaders before speed strips came into being. I still have the belt pouch to carry them. Now I just carry speed strips and keep the speed loaders next to any revolver I use for home defense, but my main revolvers all are cut to accept. I also use speed loaders/Moon Clips for car or off body carry. If I leave my rural area, I take one of my 1911's, HKs, Glocks or Sigs. with a spare mag. I do not consider myself armed with a semi auto without a spare mag or at least a speed strip.