developing new serves or perfect old ones

[tennispal]

hey
i currently have the topspin-slice serve as my first serve and a kick serve as my second serve. do you think it would be worth the time to develop a slice serve or should i spend my time working on my old serves? i want to learn a slice but i am afraid it will eat up valuable practice time for my old serves.
opinions?

[THSBOI]

Why wont you do both? then you would have more serves up your sleeves =P and then you can mix them up in a game to keep your enemy guessing

[racquet_jedi]

Why wont you do both? then you would have more serves up your sleeves =P and then you can mix them up in a game to keep your enemy guessing

*Insert nonexistent "Thumbs-Up" smiley here*