Hi E.,
I feel very blessed to be given my mother's fingernails. She had nice long nailbeds, and healthy overall genetics for beautiful nails. That being said though, there are a few factors that I've found when I'm slacking on the maintenance, it defintely wreaks havoc on my nails.
nutrition, is important. I take a multivitamin every day because I don't always eat when I'm supposed to and frankly - a granola bar is sometimes all I have time to eat between waking up and dinner.
secondly, moisture. I would suggest getting a decent nail oil. Or, if you eat avocados spread a little mashed avocado on your nails when you're making gaucamole :) avocado oil is excellent for your nails. Olive oil is another good choice. The oil will prevent them from drying out (washing hands a lot will do this)and prevent layers from splitting away from eachother (we have 7 layers of nail...)
third, the WAY you file can weaken the side of the nail... file in one direction, and not a saw like motion... avoid filing the sides of your nails.
fourth (sorry its so long already but this is another important factor), avoid polishes that contain formaldehyde. It is inredibly drying to the nailbed. Sally Hansen has formaledhyde free polishes - honestly I haven't checked the labeling of others... i stick with either OPI (salon brand) or Sally Hansen.
Getting fake nails is terrible for your natural nails. I've had them a few times and only kept them on for short periods (like the 2 week period of my wedding and honeymoon). It took my nautral nails a month or two to recover and get back to 'good'.
My mother was a licensed nail technician so she taught me how to take care of my nails.
If you've done all these things and still have issues, you may want to talk to your doctor about it, as many health issues become prevalent in our fingernails before we see major symptoms elsewhere.
Good luck, and God Bless