Your body will get biotin from foods like almonds, walnuts, carrots, fish, spinach, yoghurt, eggs, soy, etc., I take supplements just to give my body a boost because while I try to eat healthy (I shop at markets to get a big variety and like unique foods I don't generally find in supermarkets), I don't know exactly how much of everything I'm getting and I like to top it up.

A good diet is going to be the thing that helps most, supplements are just that, supplementing your diet with a few extra vitamins/minerals. Of course this comes down to what people can afford. 10 years ago my options were $1 bread and 60c noodles. Now I have a comfortable income and can afford to eat well and buy supplements.

A lot of these tablets and things may not have a huge amount of what you're after in them either, topped with the fact other vitamins and minerals can inhibit absorption plus the fact tablet forms don't absorb well as I mentioned.

When it comes to supplements, the ones I use are Hubner Silicea Gel- which I can just add to water as it has no taste, Spatone liquid iron- as it comes in sachet form and I can't be bothered measuring things out every day, and a liquid multivitamin and biotin tablet from the health food store.
Drinking more water will help, which in turn works 2 fold if you did add something like silica gel into it (silica is in a number of foods like rice, but because of over processing land it is becoming less measurable in foods), and increasing foods with things like zinc, protein and iron.

Another thing is making sure to moisturise your hands and nails (or hair as the same things help hair growth too) as when they become dry that's when a lot of splitting and breakage occurs.