Conveniences

The train system is very flexible so you do not have to make reservations or purchase tickets in advanced. Just know where you are heading to and the timing you want to board the train, be at the ticketing counter some 15 mins or so earlier ( if there is no long queue), show your KTX pass card and you will get the train ticket to your destination.
Oh yes, it is possible to purchase multiple tickets in advance. Say you want to take a train from Dongdaegu Station early in the morning and would like to get hold of your ticket the day before? Sure you can, as long as you have the time and date in mind, you can get the paper ticket first and keep it for the next few days. 

Simple!
Seats allocations will be done and if you prefer window seats just tell the staff.

With a KR PASS, you need not dig out our coins or notes every time you want to purchase a ticket, so it is very convenient.