While safety may not be an issue, adding chlorine day every 3-4 days requires that your FC level ride on the higher end of the FC-to-CYA ratio. The higher the FC over the CYA the more susceptible it is to the sun's UV rays because they're is less stabilizer for the FC to bind to. That's one reason why we have to add chlorine more frequently during a SLAM. This can also be a problem for some pools that have intense heat and require 3-4 ppm of chlorine per day, so someone in that position may need to add 12-14 ppm of chlorine until the next dose. Again, not impossible, just not ideal. A classic example of when this cannot be avoided is say a shift worker like a firefighter who works 3 or 4 days straight. Or perhaps someone who will be on vacation away from the home for a few days.