I use 2 for each PC backup so that if one fails I can still get data from the other. Same should apply to any portable device to really but I haven't got anything I'm that bothered about losing. Important family photos I usually print a copy of on photographic paper and put them in an album with the rest. Maybe I'm old school but I prefer looking at and keeping photos in hard copy. I too use Google Drive and also Dropbox for sharing files and photos with friends and relatives.