male cats can develop infections and/or crystals in the urinary tract and they will pee in places other than the box - partly due to being blocked and the urine leaks out and partly just basically letting you that there's an issue.
if not treated, a blockage can kill. i almost lost my rusty just this past spring due to a severe infection/blockage.
keeping the boxes clean is important. especially if you have male cats - their urethra is much narrower than a female's so, they are naturally more prone to developing issues.
to remove urine/feces odors, wipe up excess and treat the area with 'nature's miracle' that stuff is fabulous at removing these kinds of odors. if you've already treated the area with some other type of cleaner, it may take multiple treatments of the nm to remove the odor...
cats have really sensitive sniffers and, even if YOU can't smell the urine, THEY can, so, cleaining with anything other than an enzyme-based product will not remove the temptation to repeatedly go in the same spot.