I have 4 cats and only have 2 extra giant litter boxes. I would get another one but don't have any more room for it. I usually only scoop once a day in the morning. If I have time or notice that they're really messy, then I'll scoop again in the evening too. I use EverClean Extra Strength scoopable litter and just add new litter to the old when it's needed. I also use 2 Johnny Cat litter box liners per litter box and change these as needed. I've never scrubbed their litter boxes out with bleach. Is this really important?
I have covered litter boxes and if they accidently spray on the inside of them I use Simple Solution which is a stain and odor remover and is safe for pets. People never smell any kind of cat odor in my condo so the litter and spray must be doing a great job.