i stopped taking probiotics after a while, and i recommend the same. you're right that once things get better or repaired, there's not a whole lot of continued repair going on. it certainly won't hurt you...except for in the wallet. good probiotics are expensive.
however, if you stop supplementing with a pill form probiotic, i would consume food based pre and probiotics as often as you can. so, the fermented foods like kombucha, kefir, kimchi, fermented pickles, etc. and plenty of dirty food and ocean plants.