In my experience it still makes sense to estimate together using the same story points (or T-shirts) when there are people ranging from almost no experience to

In my experience it still makes sense to estimate together using the same story points (or T-shirts) when there are people ranging from almost no experience to very senior ones working on a project. 1 SP for a senior may take 1h of his time and for a junior that would be 2-3 days but it's still 1 SP - a relatively simple task. This is in contrast to a fallacy of recalculating SPs to time-based units cause if we do that we might as well just estimate in hours/days. It's about agreeing on some baseline first (what does 1, 2, 5 SP task look like?) and going on from that. We just need to remember that velocity will be different for different people so team capacity calculation is going to be all over the place but I think this approach can be useful.