Retire because you enjoy leveling up, i'd say. Don't do it for the 'looms, they aren't worth it if you hate being <30.
I made an alt for every build i like (2h, pole guy, archer, STF HA), so i can switch to those anytime i like. Quite a luxury, i think. When a cav map comes on, i switch to my main 1h cav guy or do a few rounds as HA... when a cramped infantry map comes on, i bring out my 2h guy or pole guy or my archer.
I would recommend making 1 main character and start with one or two alts. If you are a casual player, i would recommend not retiring and making a few alts instead.
In short: make main -> level to 30 -> make alt -> make alt -> make alt -> reach level 25+ with alts -> consider retiring main.
Something like that anyway... but just do whatever you like!