[theK]

I think writing good cache support _can_ be very, very hard.

But in cases as grandparent describes, you do have significant wiggle room.

[ChrisMarshallNY]

I write native apps (see "not my bailiwick," above).

It's fairly difficult, for me. The app can do a lot, but sometimes, the data needs to be fresh. Making the decision to run an update can be difficult.

Also, I write free software, for nonprofits, so the hosting can sometimes be a bit dodgy.