Layering a wax is always a good idea, 2 coats with a 24hr cure time between coats is the trick. Washing the car - theres a few ways you can do it, two bucket wash with a non-abrasive soap (dedicated car shampoo basically), rinse down, and voila. As long as the water is beading off - you know your wax layer is fine. Dry the car down. Then if you want that 'just waxed' look, use some quick detailer and mist the panels sparingly and wipe off with a microfibre towel - this will give it a really nice glaze look, but only tends to last about 5 days.
Some people swear by washing and quick detailing, its a preference thing.
When it comes to claying - you only need do it when the paintwork begins to feel rough, as a guess, 6 months would be about right. Again, polishing becomes neccessary when the wax layer has been stripped off - to get that deep shine again.
Depending on the quality of your wax, it can last anywhere up to about 6 months, easiest way to tell is just check for beading after a wash. When it needs renewing - your best either claying the car - which will remove the wax/polish layers, or do a fairy liquid car wash - which will also remove all wax/polish. Then set about polish and waxing.
Mine has got a little dusty, so I'll just rinse with a hose, then give it a quick soap, then rinse and dry off.
BTW where are the before and after photo's of your epic car clean, you've got to show us what that £90 can do!
