certain supplements and diet modifications can help. Silica, flax seed oil and calcium to name a few. It is also a good idea to use a good heavy duty hand balm (a gardener's balm is good) to keep them moisturized.  Wear gloves etc.  File them smooth so they don't catch on things.  Drink lots of water, basically anything that keeps skin and body moisturized.  I hope this helps. 

It doesn't hurt to mention it the next time you see your doctor.  Fungal infections, deficiencies, and autoimmune disorders can all affect nail health.

There are polishes to help growth and strengthen nails; not sure if you'd be interested in having clear polish on them though.

Grow hoofies -- they're cuter

trishcuit mentioned supplements.My nails used to split or sort of "peel" in layers. I find taking a multivitamin helps a lot, especially if you might not be getting enough of everything in your diet (which can happen when you're super busy,/ not paying attention sometimes). I assume you're not trying to grow them long, just keep them healthy. Some people put almond oil or something like that on their nails. I bought something called a buffer. if you want, ask the cosmetician at the drugstore for a nail buffer...you can get one for about 5 dollars I think. It's a "nail file" type of tool, that polishes (no colour or anything, just healthy looking)  and smooths the nails without puting any oil or varnish on them.

My sister in law swears by flax seed oil. You can get it in capsules, or you can buy flax seed and start adding it to everything.  She had nasty adult acne and it helped it, her hair looked good and she said her nails were amazing.  When she stopped taking it for a bit everything reverted. 

Being prenant does wonders for hair and nail growth too but that's not an option for you I  guess. 

Thank you all for the advice. I think mainly I have to stop drinking so much battery acid and start drinking milk instead.

Congratulations MC jae on quitting the habit of nail biting - I'm sure it was not easy!  I don't have any tips or helps, but appreciate the ones others have shared above.  I hope the health and strength of your nails improves.

Thank you Beloved. It is such a nervous habit. Please pray for me.

Rich blessings.