I still fly plane with retracts.
You can use regular servo on the retracts using ATV to adjust the throw, but I do not recommend it. If anything prevents the retracts to fully retract, the servo may strip the gear, if not continuously draw power off the battery pack.
A well setup retracts, stays trouble free for a long time.

If you compete in a Pattern Contest, make sure that the gears do not extend during flight. If one gear comes down during flight, I believe there is a downgrade.
If you are looking for a very slightly used retract servo, I have one of Futaba 136G available (I fly JR, but use Futabe 136G). PM or E-mail me directly.
Decision is yours.

Ihncheol Park