How to schedule an auto email for a upcoming date

[RonM]

I run a vacation rental biz and want to automatically send guests a welcome email one day prior to their check-in date.  How best to accomplish this?

[TeeSee1]

Run a bot on a daily basis against a filtered set of rows on your check-in date

[LDOsedea]

Is there another way to do this?

For example, if we have a list of users and their check in time, it would be nice to send an email an hour before the checkin time. 

That value would be dynamic so using the default scheduled option wouldn't work because you can set 1 time.