I find that BMW paint with swirls requires some pretty aggressive compounds, Meguiars M100 with their microfiber pads have some serious cut and still leave a good finish. Usually good enough you can follow with HD Polish using either a microfiber or foam polishing pad. Try a few waxes and sealants, find the one you like best and use it as often as needed. I have Opti-Seal, Optimum Car Wax, Collinite 476, Clearkote Carnauba Moose, Souveran, Paste Glaz and even Mitchell and King Rannoch wax. All have their own particular strengths and look. Since appearance is subjective, it's best you try some on your own and go with what you like best, not necessarily what is the flavor of the month on detailing forums.
What accumulator means by polishing once a year is that you should have a good enough wash technique that keeps the paint looking good at least a year without polishing. For me, that's ONR (aka Optimum No Rinse), plus its a much faster way to wash your car than more traditional methods, uses only a couple gallons of water and whether you use the regular version or the wash and wax one, your car will also look better than if you had washed with a hose and regular car wash soap.
What accumulator means by polishing once a year is that you should have a good enough wash technique that keeps the paint looking good at least a year without polishing. For me, that's ONR (aka Optimum No Rinse), plus its a much faster way to wash your car than more traditional methods, uses only a couple gallons of water and whether you use the regular version or the wash and wax one, your car will also look better than if you had washed with a hose and regular car wash soap.