How does one know that their finger nails are unhealthy?

When your fingernails are brittle or change to a yellowish color, it is a sign that they are unhealthy. I’m not sure if the nail polish or the nail polish remover affected your nails but since you noticed a difference, stop using it for a while and see if your nail’s condition improves. Make sure you don’t have any sort of fungal infection. Also look at your diet to see if you are eating healthy.

They fall off.

They get discolored, break or develop ridges. Talk to your doctor is you notice the changes.

I used to get my nails done professionally, and when the polish came off, they were much more brittle and discolored than when I went the natural route. I’ve given up the polish, and as long as I have a well-balanced diet, they grow strong and quickly.

If they crumble, are discolored, are ridged, or have black spots on the end. Ask you doc to take a look at them.

If they’re constantly chipping and breaking too easily and are very brittle, they’re probably not as healthy as they can be. I’ve also had my nails done with a gel overlay one time, and after it came off (which is about a month or so ago), my nails have been the worst they have ever been, i have to keep them as short as possible because they’re breaking and tearing and whatnot. So what you put on your nails can certainly affect their health. I think that generally wearing nail polish everyday for extended periods of time can have a negative effect on your nails, so i wouldn’t wear it often. However, normal nail polishes don’t seem to be nearly as harsh as acrylic and gel overlays that you get done at the salons, i’d stay away from that if i was you, i did it once, and NEVER again!
Also, my sister drinks carrot juice everyday, and your nails immediately start to grow stronger. Obviously it’ll take a while, while you’re nails grow out, for you to see the effect. But her nails are much stronger for drinking carrot juice. She has a juicer, so makes a glass of carrot juice every morning. I want to do it to (i’m just so darn lazy to do it and clean the juicer everyday! haha). So…....try the carrot juice!

Thanks everyone for your responses :) I’ll take it all into account.

Dry breaking and brittle nails are a sign not only of unhealthy nails but could also represent an underlying health problem. My nails are usually a nice clear color I noticed when one of them got infected it turned brownish and dark. They have several products to brighten nails and oils to help keep them moist and stop cracking and chipping. Try using some of them and a better brand of nail polish.