Personally, I carry a 27' aluminum extension ladder. I only put the ladder on the ground (grass, sidewalk, patio) or on a wood deck (assuming there is a staircase to get it up there). I do not put my ladder on roofs to get up higher. I've seen inspectors puncture rubber and rolled roofs, so I don't put my extension ladder on these types of roofs. If I can't reach a flat roof safely from the ground (or a window), I note that it is not safely accessible in the report. I don't want to be a statistic. For pitched roofs, I see what I can from the ground using visual aid. I get up on just about every single level (ranch) and split level, unless weather conditions prevent safe access. My ladder reaches most 2 stories houses as well, although if the ladder barely reaches the gutter, I don't chance it. I see some old 2 and 3 story row homes with roofs that I can't reach, although many of the 3 story units have a rear addition that I can get out the rear 2nd level window and see the 3rd level flat roof using a step ladder. For flat roofs that I can't see at all or get to with the extension ladder, I simply note that is it past the safe access of a 27' ladder and recommend consulting a qualified roofer to certify the remaining life. Most roofers around here carry ladders much longer than my 27' extension ladder and if they do put a ladder onto a roof to get higher, it is up to them to repair it. Also, if the ground, ladder, or roof is wet, I do not go on the ladder. I do a visual inspection from the ground and note such in the report. Many inspectors in my area either carry no ladder or use one of those Little Giants... no idea how they get to 2nd level flat roofs. I assume they do it from the ground with visual aid.