As a beginner, it seemed like my nails would not stay grown for love nor money. Spits, cracks, dings, you name it. Especially my thumbnail. At first I tried cutting and supergluing ping pong balls, which worked okay and which I would still resort to in an emergency. Then I started using polish. And now my p nail is a wonder to behold.
I began just using Sally Hansen clear from the drug store, and now they stay long and are strong enough to play naked if I want to. Absent, that is, a real trauma like a couple of weeks ago when I dinged my a nail loading luggage into the car. (Oh well. Once in a while it's gonna happen no matter how careful one may be. Anyway, the way I see it, a broken nail can be chalked up as an opportunity to practice attacking the string with utmost accuracy. See "Things to remember when you play scales (Spanish Guitar)" by Grisha Goryachev on the tube. Plus, there's always ping pong balls if necessary.)
A regular here -- I forget who -- suggested OPI Nail Envy which I bought online in matte which eliminates most of the shine you get with clear. It is now my favorite polish. Talk about bombproof. As a matter of fact, it takes quite a workout with cotton and a remover to get the stuff off.
Attitude is more important than the past, than education, than money, than circumstances, than what people do or say. It is more important than appearance, giftedness, or skill. -W.C. Fields