I have an S, and a Roadster...and an X reservation. That would be three cars for two drivers; that is overkill. We are happy with the cars we have, so I'm not at all sure we'll be getting one.
The X reservation is partly "just in case"...what if one of our cars are stolen or damaged and we need to replace it? I want to have as many options as possible.
It's also in case our situation changes. We currently don't need a bigger vehicle, AWD or towing capability; but we're looking at homes where AWD may come in handy, and my wife wants to tow a folding camper trailer (me, I'm happy driving the S to a motel). I am in love with the Roadster right now, but I have a degenerative joint disease and at some point it might be hard to get in and out of. I am hoping that is many years away and the third-gen car will be a suitable replacement; but again, I want to have options in case it becomes an issue.
And to be honest, the reservation is partly because it's always nice to have the latest and greatest and show people that, yes, EVs can be big and have AWD and tow and all those other things they assume are impossible...I may be looking for an excuse to get it, rather than really having a need for it.