Re: Bad Rope (Line/Sheet) Advice?
As has been mentioned there really isn't enough information here to tell if you got good advice or not. Going smaller on halyards is pretty standard good advice, the same for outhauls, topping lifts, ect. Sheets really depends on what you had and what you went to.
Basically my initial thought is that you probably didn't get bad advice, but may have been talked into higher tech lines (though not necessarily at a higher price) than you really needed. The upside is that most modern lines actually last longer and have better abrasion resistance than older stuff.