I've had similar situations where what initially seems like a simple change between async vs. sync can turn out to be a major redesign effort. Therefore I'm sta

I've had similar situations where what initially seems like a simple change between async vs. sync can turn out to be a major redesign effort. Therefore I'm starting to lean on the idea that I should use more async -methods from the start than what I'm currently doing. Part of the issue is that 'sync' is the default. I wonder if it would be better the other way. Because sync is the default it is easy to "simply" write sync methods in cases where async might be a better choice, and, that decisions is often hard to reverse later. I'm working with JavaScript but I assume the issues and questions are similar as with c#. I think the question could be rephrased as "When should I NOT use async methods?"