Yes keeping the tank clean is very important. I don't want to hijack the thread but i would recommend scooping out poop on a daily basis.
How often you do a full tank clean depends on the substrate but i do a full tank clean once a month.
1. Take your reptiles out of the enclosure and put them in a back up tank or something they can wait in comfortably whil you clean their enclosure.
2. Remove all the furniture (wood, rocks, hides, dishes etc)
3. Remove background if you have one.
4. take your tank, furniture and background in to the bathroom(easier to clean up any mess and water that will get on the floor.)
Give the tank a rinse down with hot water then empty out the water and let it sit for a minute. Then use a cage cleaner spray(or whatever you want to use to get your tank clean) and give it a real good spray. leave the spray on it and leave it for a bit and go clean the tank furniture and background.
Wash and sponge over them with hot water is really all you need to get them clean. you can use the cage cleaner spray on the rocks and fake rock hides but i wouldnt reccomend spraying any of that stuff on wood or the background.
Scrub the tank all over with a CLEAN sponge and then rince with hot water and let it dry.
Make sure its all completely dry before putting everything back in.