Your gearing is your business, your body, your comfort, not anyone else's - not ours and especially not your friend's.

For one thing, there's absolutely no reason to be running around with a triple that you can't use. Swapping out the crank is expensive - if you need a narrower crank, that would be a reason to do it - one free shifter just doesn't make sense.

Basically, it comes down to two things:

(1) the range of grades where you ride, and

(2) the width of the "power band" of your legs.

If you WANT to swap your triple for a compact, and you're comfortable spinning in a wide range of RPMs, then it's *very likely but not definite* that with a 34T small chainring and a change of cassette (and possibly rear derailleur) will give you a range of gearing even wider than you probably need. A low gear of 34x32 is lower than the 30x25 you had on your triple.

But if you have a narrower "power band," i.e., you don't spin efficiently or comfortably at a wide range of RPMs, then the steeper your terrain, the more likely it is that you really need a triple. A compact can give you almost the same range from high to low, but it leaves bigger jumps in between gears.

No one would tell you that an inline four cylinder engine "ought" to be able to perform as efficiently at 3,000 RPM as it does at 8,000 RPM. Why should your legs be any different?