[nostrademons]

It's not hard to apply an index after the fact. You don't paint yourself into a corner by leaving them off initially.

And very often, you can't understand your data model and how it will be requested until you've actually built an app and gathered some data. Users will surprise you, and do things you never expected, and probably render 80% of your app (oftentimes, the 80% you worked hardest on) obsolete immediately.

[incomethax]

I can attest to that. We have two main "sides" of our app, one side that allows for editing of rules and another that just applies those rules on transactions. It took us much longer to build the editing side than than the transaction side, and when we hit users, we found out that they didn't even WANT to edit the rules. That was more than half of our app that users weren't using, even though in initial mockups/user tests they indicated that they would edit the rules.