The probiotics we have inside us are manufactured in the appendix, so if you have had an appendectomy you will probably have to supplement every day for the rest of your life, especially if you have ever been on Antibiotics ,antifungals or some medications. If you have current fungal issues, then you are probably looking at supplementing for a very long time. If you have a perfect diet and no health issues, then why worry? you could try making your own yogurt or buying a really high quality one from a health store, no grocery store brands please.
For me, I take a probiotic every day, and I give them to my children also. There are so many stressors on our probiotic community already. The hard part is deciding which probiotic really works? I have spent hundreds of dollars on probiotics that had no effect whatsoever. Natren, PB8, and Essential 12 plus work for us.