I want to be able when a user requests a service on my system to:
1. authorize only a transaction
2. capture previously authorized amount (from step 1) for a certain date in the future (within 30 days, how long the authorization code is active)
I don't think clients should be implementing some sort of scheduler for when a "capture previously authorized transaction" should occure.
A use case would be car rental:
Online I book a car and provide my credit card info.
The rental company authorizes my credit card and does the capture on the date when the rental date is set.