I had my roof replaced maybe 6 years ago. My house had very expensive milled wooden gutters (1973) that were rotten. I removed the old gutters and pulled down and replaced the punky Facia boards with new Redwood Facia...primed and painted on ALL sides Before they went up.
I did NOT replace the old wooden gutters with ANYTHING. Everything has been fine so far. The roof is a Raized Ranch with a slight/moderate incline....In Rhode Island.
I paid attention to many roofs I noted around the lake and elsewhere north of me. If I lived up there..I would likely have a steel roof....no gutters.

NB
PS: I don't have any trees hanging over the house.