That's a good question. It is something I spend a lot of time thinking about when I see how users react to a design. In this case, I don't think I have a good answer as to why "when" seemed to go down easier than "if".

> Do you feel like you've developed a better instinct for this over time, or is it still hard to predict what will feel natural to users?

I'd like to believe so, but "if" was my first pick, so I guess not. :)

I think what our team does have now that really helps is better processes to evaluate a design, talk about it, get feedback from users, and incorporate that feedback into the design. It's all pretty informal, but I think we're iteratively able to get designs users seem to like.

But it's always really hard. There are so many trade-offs and users have different preferences and expectations, so finding the right balance is always difficult. I think that's why it's so endlessly fascinating to me: you can never fully "solve" syntax design.