It kind of depends. You can do the inspections and sealing yourself with off the shelf products. You'd be more likely to spot changes in the seals, but you'd have to climb a ladder. If the cost is reasonable and you think they've done a good job, there's no reason to change.
Washing and waxing can be done with something like WashAll WaxAll which is a waterless process, but again, it's a matter of time and effort vs cost.
2015 Dynamax REV 24TB class C