I'm anticipating very few customers with very many recurrence rules. Well in that case why bother? It hardly matters what approach you take if you're not planning for lots of users. Surely your server has the power to compute tons of calender data for just a few users.

Heh ... I didn't mean the system would have very few customers: I meant many customers, but only a few with a *lot* of recurrence rules (i.e. enough to be a burden to a minimally-configured client).

But I have a nagging sense that the case you're presenting isn't actually possible. So much work that your server can't do it, but so little work that you should hand it off to some Javascript to run on the client. I just can't imagine when that would be the case, but perhaps I'm getting too used to having really beefy servers.

You're probably right. It's getting difficult to *not* have a beefy server any longer.