Just keep in mind that a premium price cannot always be extracted from a premium kept car. It was not a fun thing to find out, but no scratches on the rims (winter and summer), no door dings, weekly details, garage kept, and neurotic maintenance schedules do not translate into a higher sale price. At least over here.
Keep it looking as pretty as possible for yourself, and yourself only. I am much more relaxed (but not lax) about my new M3 than my previous cars, after seeing my most recent car sit on the market and depreciate after chopping the price a couple of times. I would not mind keeping it, but in the end I only drive the M3 anymore.