Older units still in service

[PastorMP]

Good afternoon POG, I'm in my early stages of looking to purchase a used coach. My question for the group is: If I purchase on good used coach about 12-15 years old, what's is the life of the unit and more particular the systems on board. At this age are the systems more prone to fail? Is new complete systems in the near future? I'm asking about systems like electric and plumbing also windows. Do these systems tent to last many years with minimal service. I completely understand, tires, A/C service, generator maintenance, batteries (all batteries Included). I read here for some time. I got it. I just haven't seen anything on older units in service. Possibly I'm overlooked a thread somewhere is so I do apologise and please send me to the correct thread. I'm looking for input from anyone. Thank you and blessings to you all.