Well, being lazy and picky, here's what I do. First, garaging a car will make the finish last the longest. Like you, I prefer Maguiers for a cleaner and polish. For leather, very diluted Windex water combo works to remove light dirt. I try not to use a leather treatment like Lexol, which I have both the cleaner and conditioner, as I like the low gloss look for the leather. Even using the Lexol cleaner will make the leather shiny. For any cloth or carpet stains, Armor All products has a new Oxi-???? product that works really well.
As to the outside, like I said above, I am lazy. That means I hate to wax a car. I park all of my autos in the garage every night. I also only wash them with cold water, no soap or cleaners, and in the shade. This really helps to keep a finish on a car. My wife's Volvo convertible is 3 years old now and it still beads up, never been waxed. I wash it about once every two weeks as lately it mostly sits as she is using the Denali mostly. My Jeep Wrangler, seen every kind of weather and driving condition. But again, washed in cold water in shade, sits in garage when not on the road. Still holding a good shine and beading.
My diesel motorcoach has what we MH'rs call full body paint. (Basically painted all over like a car) When it needs a wax, I'll hire someone. But I do wash it every time I take it out, usually about 1-2 times/month.
