I got one for my mother two years ago. An expensive item as the rail for chair is purpose made for you stairtrack so no resale value. It was possible to get a second hand chair though. But worth it in the end for extending life in her own home. It involved a very detailed survey as initial visit, I think over two hours of measurements/video. That surprised me as thought it would be brief visit and then a quote. After order was made, there was a three week lead time and several hours on work on the day of installation. We opted for extra electric switch for a foot plate rather than a lever. It operates very simple with control on armrest, up or down and stop, and with two remote controls as well for upstairs and down. you will need to have electric connection at the ground floor to top up the battery but they installed same.
So pleased overall and has been used ... would have been worth it even for a few months to keep mother at home and not in care home. She will be 100 tomorrow. She lives in UK and Stannah was the company that supplied same. I was impressed that no permanant 'damage' is done to the fabric of the house and if removed, you would not be able to see where it was as supports go down into the floorboards thru carpet.