Regardless of whether you do any maintenance yourself (supervised or otherwise), it pays to know which jobs are due, and why. Which jobs are mandatory, which are necessary and which are optional. On the optional side, presuming that you actually want to keep your investment from being hollowed out, you need to be able to converse with the people who service your aircraft and participate in the preventive maintenance planning, not just give them a blank check and remain ignorant of what happens behind their closed hangar doors.
An owner does have a mandate but can only exercise it if he is suitably informed.
Too often you pay just for paperwork and procedures and a cursory look, with nothing to show for it when your plane leaves the hangar and you get the big bill, with things not done that would have been in the interest of preventing future costs.
Originally Posted by IO540
One should not use a company unless they are familiar with the type.
You are right of course, but sometimes you have little choice. If the type is uncommon, some of the people working on it might not have sufficient experience to perform all tasks efficiently.
I also meant "familiar with the aircraft's history" here. If you present an aircraft of a known type at a place where they've never seen the aircraft, the annual will include extra work spent on checking the standard of previous work. (EASA introduced an unworkably rigid fixed-base rule for ARC CofA's, but they do have a point.)
Justiciar -- How old is the Permit aircraft? How important to you is it that it is kept safely, that you and other users, potential buyers and other parties know that it is kept in top condition?
Under Permit a lot more things are at the owner's discretion, but if you want to keep everything in top shape the work would still need to be done somehow.