To the original question, there are probably 4 aspects to it - functionality, fit, tone and appearance - and probably in this order of importance. Honestly, I wouldn't change out a bridge unless you were having issues with intonation or structural stability (aka functionality). Several years ago, I had a Ric and the original bridge gave me some trouble with intonation and tail lift. I chose to replace it with a Hipshot drop in replacement bridge (no need to drill new holes - aka no problems with fit), which fixed the functionality issues. I did choose the heavier brass version of the Hipshot bridge, thinking that the higher mass bridge would give me something extra in terms of tone, but I couldn't really hear any differences. To some the new bridge looked cool, to others, it didn't look right because it wasn't the original bridge. I didn't care because everything worked and fit correctly and sounded fine.
Today, I play a Lakland, and the bridge has no structural, fit or tonal issues. There are some people who don't care for how a Lakland bridge looks, but for me it's fine.