Used these to hang wreaths and a swag on windows. One hook has fallen twice. Two others have fallen once. One medium that I purchased to help distribute the weight of the swag also came off and the other loosened. I have managed to get 3 of the large hooks to remain up, two for 3 days and one for one day so far, but have had to use all 8 of the adhesive strips that came in the four packages to get those 3 to stay. In all cases, windows were cleaned well with window cleaner and dried, hooks remained up for over an hour before hanging the wreaths and swag. I use the indoor hooks often and have not had issues with those.