Don't laugh. At our previous 2 story home we had 12 lighting fixtures all around the exterior of the house mounted about 23 ft high. This was before LED bulbs and even CFL's wouldn't last more than a couple of years. Also, the AC condensers were all on the 25 ft high roof - not easily accessible to techs for servicing. The house did have at least a 3 ft wide stone or concrete walkway surrounding the entire perimeter. So off to ebay I went
where I found an old but working 30' Genie hydraulic manlift being sold by the Biloxi MS Airport for about $900. I bought it and called a freight company to get it and it served me well for the 10 years we were there. I even sold it to the guy who bought our house!
It did have one problem that couldn't be repaired (no parts) - when you got to your desired height it would immediately start to slowly sink.
Enough time to change a bulb but if you got out on the roof for even a minute it would leave you stranded up there. I bought a little 4 ch wireless remote control relay and spliced it into the manlift control wiring. Press the 1 button for up and 2 for down. As long as you had the fob up on the roof with you it could be brought back up when needed.