Gel stain on bare wood will be the same permanence as a liquid stain. If over a previous finish, it will wear off if the finish coat wears off. So use a tough finish coat, like a floor varnish.
If oil-based varnish is used, either make real sure the gel stain is fully cured, or use a separator coat of shellac sealer to prevent the varnish's solvent from disturbing the stain.
Casey

I also want to know about the same relevant topic and I agree with idea of sombreuil_mongrel.. Thanks for sharing.

Any pigment stain is sitting ON the wood, and will wear if the protective coat wears away exposing the stain.

Dye could fare a little better, but depending on the type of wood the penetration can be very slight.

Any coloring is going to rely on the clear coat on top for wear protection.

Hi bus_driver
May I ask what brand of urethane you used on your stairs?

I have a set of fir stairs in my home that I am currently sanding down to finish...haven't decided what I am going to finish them with however! I will not be using a stain/color on them as I like the natural beauty/color of the fir. Simply need something to 'clear coat' them with for protection and was wondering what product you used...and why you wish you would have done a few extra coats.
Cheers

I have a steps finished with a honey oak color and four coats of polyurethane. I would like to darken the color. Is there a way to do this without removing the old finish?

i'd go with ebony. the more applications the darker it gets with out going totally black. it's a dark, dark warm gray. and it's a standard color in the world of stains. as far as the clear coat goes, you need a floor varnish. personally i'd use a marine varnish despite it's price. if it doesn't hold up, then stop walking around in cleats:-)

Seven years ago, we finished our oak stairs with 3 coats of polyurethane. They look great yet.