Technically everyone has some experience with them, seeing as they are part of the natural digestive process. As for taking a supplement, yes. I start taking them anytime I am prescribed an antibiotic. A few years ago I was pumped full of some of the strongest antibiotics made after a post-op infection. Since then even the mildest antibiotics can set my system off balance.
Everybody has probiotic because it's found in basically everything, but in pill form, my dad used to take it for IBS. In the first week it made him really constipated (he had to go to the hospital), then he never had any digestive issues ever again in his life.