Which Brands Tend to be the best for user-replaceable Parts?

Thats a very subjective question ;-}

It all depends on what it is and the given devices age.

Most major manufactures have reduced the availability of their parts in one way or another.

• Some have reduced the number of discreet parts focusing on more sub assemblies which can sometimes make a simple repair overly costly.
• Others have focused on supporting their support partners so independent service companies have no access at all.
• And lastly, limiting the availability of parts for a set limit of time.

They all fail in one way or another.