I did retirement care for many years before building my indoor. I do not approve of the lump sum model at ALL.
Most elderly horses will have some sort of health issue at some point that requires expensive care, but they aren’t really ready to go yet. I would be wary that a lump sum place would just put them down, rather than doing something fairly easy like testing for Cushings/Prascend, etc.
I will say I selected retirees whose owners were devoted to their horses and with plenty of money to spend. I could text them that their horse needed fly boots/a new sheet/whatever and it would arrive from Smartpak no questions asked. I also structure my retirement board so things like fly spray were built in, so I didn’t have to nag them about supplies.
My oldsters have all passed on at this point, but I kept them through my business change…I get really attached to them. Luckily I have a big “back field” that nobody in the training business wants to use because it’s a hike, so the retirees fit seamlessly. Now one of the training clients has a retiree and I have a retired pony of my own, so they go back there.