Strategy- Low Grade Rare, Or High Grade Less Rare

Just looking at some coins I'd like to collect over the years and I'm trying to decide what's a better long term goal. Do you go after the more rare dates/mints in the series, knowing you can't afford a mint state coin? Or do you get a few less rare dates in really high quality?

Specifically today I was looking at Peace dollars. Most dates I can get a MS graded/slabbed coin for well under $100. But the rare 1928 (P), the MS coin is going to be $800+. So do I buy 10 of the more common dates, or save up for a long time and buy the one rare coin of the series?

Or a more extreme example, do you get an AU-03 graded 1916 D Mercury dime for $500, or a few of the less rare dates in MS63-65 for under $100 (or even $50) each?

What is your strategy?