How are you going to use the data? Set the lead time before a specific appointment date/time (then use DATETIME) or lead time in general before appointments (then use INT)? Maybe you can give a little more information about what you're doing?
It's an application for appointments. The admin has to set the minimum appointment time so the user won't schedule the appointment, let's say, 10 minutes before the service is supposed to be worked on.
Let's say the admin sets the minimum lead time as 1 day. That way, users cannot schedule an appointment 8 hours nor 4 hours nor 1 hour nor 10 minutes before. They have to do it at least 1 day before the service is supposed to be executed.
So the admin, on his settings panel can select from a drop-down menu, the minimum lead time. It can range from 1 hour to 2 days. Whatever the admin picks, needs to be stored on the database.
My question is, how would you store that setting into the database? That value is to be checked on by the application everytime someone tries to schedule an appointment.
How would you store the value 2 days in the database? How would you store 4 hours in the database?
As long as your application will never need to allow more hours than TINYINT will hold (255, I believe). So if someone decides they need more than 10 days in the future, you'd have to change the field to SMALLINT.