Is it worth buying extra toolheads just to keep different nozzles mounted?

Most people who need that kind of flexibility eventually just bite the bullet and buy a couple of spare toolheads. It's a hassle, but the time saved on swaps is huge. You mentioned the issue of getting the exact nozzle type, and honestly, I found the same limitation. Snapmaker doesn't offer custom hotend configurations, so you are stuck with the stock 0.4 nozzle when ordering a spare unit. If you are serious about having specific nozzles, your options are limited to modification or buying aftermarket parts. You can buy the base toolhead assembly, which usually comes without the hotend installed, and then swap out the stock hotend for a different size or type yourself. You just need to make sure the replacement hotend has the correct heater block and thermistor to match the toolhead's electronics. This requires a bit of mechanical skill, but it totally solves the problem of getting that 0.6 hardened nozzle paired up with a ready-to-go head.

I dealt with this when I needed a dedicated tool for carbon fiber filament, which demanded a hardened steel setup. Instead of buying a whole new toolhead that came with a brass nozzle I never used, I bought the bare toolhead chassis and sourced a compatible 0.6 hardened hotend from a third-party vendor. Then I installed it myself. It saved me the cost of a few unnecessary nozzles and got me the exact toolhead I needed for the job. If you're only doing occasional swaps and need a small collection, maybe focus on getting the specific nozzles you need first, and then use the same toolhead assembly, replacing the nozzle when you switch sizes. But if you are constantly switching between three or four different types, going the full toolhead route is probably the best long-term investment for your time.

The suggestion to bypass the stock hotend and just get the bare toolhead assembly is definately the way to go if you want specific sizes. I ran into the same issue trying to do some tiny detail work where the standard 0.4 brass nozzle was just too chunky. I sourced a smaller 0.25mm hotend head myself and swapped it onto my chassis. It took some time and a bit of soldering to get it right, but once it was dialed in, the difference in print resolution for those delicate parts was huge. It’s way better than having three full heads sitting unused.

Beginner here so sorry if this is obvious, but does each toolhead remember its own settings once you've dialed it in? My situation is a bit different, I only switch between two materials so I've just been swapping nozzles on the one head so far. If the machine has to relearn the bed height every time I pop a different head on, then the whole quick-swap idea loses a lot of its appeal for me. Is that something you have to redo each swap or does it carry over?

One thing I learned after assembling my little fleet of heads: label them, and keep a small bin with each head's spare seals and the specific nozzle sizes you run on them, because six months later you will not remember which one had the 0.6 hardened nozzle versus the worn brass one that prints fine for PLA. I also stopped feeling bad about the unused 0.4s piling up in a drawer, since they make decent emergency backups when one clogs mid-job and you need to keep printing. Curious whether others store thier spare heads with the fans unplugged or fully assembled, because I have a nagging feeling leaving heaters installed long term is fine but I'd like to hear if anyone's had corrosion issues on the contacts sitting on a shelf.