I know.. I never take it lightly. But I also never regretted it either, probably because I really do spend some time on making that decision, and know I would do it again. Excuse the bragging, but by now I can even delete songs! Super crappy "songs", mind you; but it was near impossible for me at first. It's liberating however, and with photos just plain necessary IMHO.
You are not actually killing that person, or destroying that object; you are just deciding which one(s) of the photos of that moment or mood capture it best, and delete the ones which are just slightly worse variations of those.
It takes time though, that is a real cost. Though I think that time is made up for down the road, when you don't have to wade past the photos you deleted, or wait for them to upload/download/backup, etc... even a little bit of self-discipline adds up to quite a bit over a lifetime of digital photography. I think of it as removing weed so the flowers are more enjoyable, and have a greater probability of actually being seen (photographs are kinda useless when they are not seen other than by the bulge they create in the pagination; flickr is like a graveyard where good photos go to get overlooked in that way).
I've noticed that I never go back to looking at old photos. If I've been off at a special event - holidays, a conference a wedding etc, I take any photos / video that I took, and edit it into a short film using iMovie. Because the film has been curated and worked, it is generally of higher quality than the raw shots, and as a result I have noticed that I tend watch the resulting films far (two orders of magnitude?) more often than the raw photos.
I've been doing this for a about 5-6 years now, so about 3 years ago I started deleting the raw shots a few months after having finished the film. To date I have not once regretted deleting a photo.
You are not actually killing that person, or destroying that object; you are just deciding which one(s) of the photos of that moment or mood capture it best, and delete the ones which are just slightly worse variations of those.
It takes time though, that is a real cost. Though I think that time is made up for down the road, when you don't have to wade past the photos you deleted, or wait for them to upload/download/backup, etc... even a little bit of self-discipline adds up to quite a bit over a lifetime of digital photography. I think of it as removing weed so the flowers are more enjoyable, and have a greater probability of actually being seen (photographs are kinda useless when they are not seen other than by the bulge they create in the pagination; flickr is like a graveyard where good photos go to get overlooked in that way).