You've probably already picked this up from othr threads here, or if you''ve had a convertible before, but it's worth stating: do a roof fabric deep clean and re-proof a couple of times a year, depending on how much the car is left outdoors. BMW do fabric cleaner [83122352678] and proofing concentrate [83122298223] which I use, works well, and which has lasted me six treatments.
Also, don't store the roof away for long periods - this can crease the fabric permanently - and generally avoid folding a wet roof away for more than 24h. Basically, the roof is best stored up to keep the fabric stretched.
And worth using a rubber treatment like Gummi Pflege on the roof side rubber to keep it supple.
If you need to clean the roof storage compartment, be aware the hydraulics don't hold the roof up part-folded indefinitely: with the ignition left on I think it'll hold for about 10 minutes, with it off it's about 5 (see the manual). You don't get any warning that the struts are about to start moving.
And while it's unlikely, i would just familiarise myself with the procedure for manually raising and locking the roof, just in case the hydraulics/mechanism ever had a problem (see
https://www.2addicts.com/forums/show...php?p=26431633). if you do have a problem with the roof mechanism I'd recommend putting it up, rather than putting it down, even if it's almost completed the down process.