Club and charity rides are good too. But some clubs will not allow you to ride without fenders. The weather turns suddenly and fenders not only keep you from having a skunk stripe of water up your back but they keep the rider behind you dry as well. So just like stopping at stop lights and signs it's good cycling etiquette.
My commute/errand bike has front and rear fenders, my mixte has wood fenders. My road bike can not be fit with fenders or not easily. I'll check with my mechanic but don't think it can be done with such skinny tires, little clearance.
I'll need a jersey that says "But my other bikes have fenders!"
If you're thinking about cycling for errands, fun, just get a little exercise in and don't want to have to worry if it suddenly rains get fenders. Many of kinds are made here: