I have my thoughts on this question - but wanted to see what you guys suggest....
my son, 26 years/old, just moved to Chicago from Atlanta
- doesnt do a lot of travel and I dont think he will be doing much with his new job
- in ATL he flew DL and now in ORD, he is planning on moving to UA
and was asking about advice about collecting UA miles
- ok, let's start with miles? points? PQP? PQF? BIS?

...also begs the question, these days, for the average traveler of a few flights a year (and mainly in E) - does it even matter?
I guess you have to start somewhere

... and no, I am not giving him my MM companion status....maybe if he remembers to call me once in awhile I will share some extra PP
(he did enjoy ORD-OGG in F on a 787 earlier this year)