Might I suggest Armour all if you are after something that's quick and easy to use. Excellent beading and lasts a while, longest I have left it on my car so far is a month but it's still going strong, expect at least 3 months out it I think.
Another Wax I am looking at is Collinite double coat which has really caught my eye!
You will only need to wax it every 2-3 months to retain the wax coating Gib, polish removes a wax coat so like Bert said, every 6-12 months is all you need polish wise to shine the car... if you keep a nice coat of wax on the paintwork the polished shine will stay protected under the wax for the 6-12 months.