All sealed automobile fitted HVAC systems are know to leak slightly, this is currently inevitable because of materials used on flexible piping and manifold seals, so servicing will be required at some point in time. Most people will only do that when they detect a drop in performance of the chiller as these systems are designed to be "critically" charged - which means there is only a slight/small tolerance in gas charge weight and still have the system working, ie too high a charge and the system will not run, too low a charge and the system will drop off in performance and eventually stop running.
I'd think that the best plan is always take your car to an independent automobile HVAC place and not to a car dealership, or even call out an independent that is mobile as their overheads might be lower.
One thing to bear in mind is, when you move to EV, they must have a fully working HVAC system as the traction battery packs needs that to keep cool!