Here's a quick summary of the problem: the app I'm working on can have multiple payment methods added (saved) by the user. They can use them for making trips and purchases in the app. I'm not sure how to model the process of which payment method is pre-selected for the user when they're purchasing something. Here are a couple of options I've considered:
A - no built-in preference system, just pre-select the last used payment method
B - have a 'preferred' payment option where users always have one payment method as pre-selected each time they make purchase (payment method could be changed to a different one prior to purchase)
What do you think are pros/cons of each? I guess it comes down to behavior - whether you want to have a preferred option that you will use 9 times out of 10 or you switch between payment methods more frequently and want your last used option to be saved.