So, I play mostly fingerstyle guitar, both on classical and steel strung instruments. I ocassionally accompaniemants (or however you say that in english...) where I really give the guitar(s) quite a good strumming, quite violently. The strings and the guitar are, of course, quite fine (I don't massacre them! =P) - less so my nails. (I hate strumming with a pick, btw). I sometimes lose them while playing fingerstyle as well, but not even close to as often. And they get stuck on a fabric, get a small splinter off, and then the whole nail... Etc, etc.

There are loads of way to lose ones nails, and I for one hate it when I do. Do you people have any good tricks to keep your nails intact, even during "more physical" playing? I've heard there are stuff you can put on them to harden them? Well, i'm looking for anything that can help, really.

Thanks in advance!
just keep em filed nicely
you and you also do need them that long just long enough for the nail to do its work any longer just increases the risk of nail breakage
or you could learn to use a pick
you could try putting superglue on them , just a thin layer, some bassists do it with their fingers
There are many tricks I've read about over the years, and I don't know if any of them work any better than just keeping your nails well shaped and "just long enough" to contact the string.
Most classical artists want a combination of flesh and nail on the strokes, not nail alone.
Of course, if you're strumming as well, that adds more strain.
In addition to trying strengtheners like super glue or super-strong clear nail polish (the kind they use for nail repairs), you used to be able to buy "guitarists nails"....Still can:

Also, players have been known to carefully cut little crescents from ping-pong ball material and glue those on for some added strength.
Thanks for the replies! I'm not really after any kind of substitute nails (like ping-pong balls or "guitarists nails", but rather good nails of my own. Maybe I have been letting them grow too far, now that I think about it... How much should they typically protrude from the fingertip?

And it's not that I don't know how to use a pick, it's just that I feel I loose a lot of versatility by doing so =P
I used fingerpicks for years. Playing dreadnought-sized instruments with medium-gauge strings was death on my nails.
Eventually, I gave up trying to play fingerstyle on that beast and just flatpicked; using an electric for fingerstyle.
Now, I've got a much smaller O-sized instrument with light strings and my nails seem to hold up OK. I keep 'em just long enough to brush the string along with the flesh of the fingertip, as I described above.
You can try such dodges as taking Knox Gelatin capsules as a supplement; supposedly works to strengthen nails; I don't know if it works or not.