I rarely do alt in MMOs that I expect to level up to maximum. World of Warcraft remains the big exception because of the length of time I played. I had two characters in EQ2 but only one was for adventuring. I had two characters in Rift, where the second one was specifically to level with a friend who came to play well after launch. Even then, I redid the cleric and flipped back to my original toward the end since she was already geared for T2. The friend I made my second run through Rift with came to try GW2 over the holidays. Creating a character to use for that purpose reminded me of two things.
My first hurdle was deciding on a new class between the three I had in mind to try, Mesmer, Engineer and Necromancer. I had a hard time choosing between them during beta until I tried the Guardian who quickly stole my heart. Once again, I created one of each with the intention of playing until level 5 to help decide. It was hard decsion. I enjoyed them all for different reasons. I kept flipping back and forth between them but still couldn't make up my mind. When two of them hit level 8, I didn't want to go any further so I simply picked the Mesmer.