When to start looking at colleges/sixth form

[JustLooking2019]

Hi, just wondered when we should be thinking about this. Year 10 ds doesn’t really know what he wants to do but will probably be A levels.
Any advice on how he should decide and what to look for in a provider, would be great. His school hasn’t mentioned it yet

Inspired by this thread, I have encouraged DD (Y10) to look at some of the closest sixth forms to see what they offer. The only one offering the subjects she is interested in is the one attached to her current school. There are a couple of others she could travel to easily, but she would have to compromise on subjects.