Worth it to touch up my bike?
My trick is to find nail polish that roughly matches the finish. It's easy to apply, quick to dry, and will prevent rust and oxidation for quite a while.  It's not a perfect finish match, but there are quite a lot of colors that come close.

If you can't find an near-perfect match try mixing two or three colors. Just remember the basics; with few exceptions all colors are derived from shades of the primary colors (red, yellow &amp; blue) and black and/or white, e.g., orange can be derived by mixing red and yellow. Then you've got glitters and iridescents (whole different ballgame). But nail lacquers can be picked up at pretty low prices and if you're not good with mixing colors find a friend who is. You should be able to get a near-perfect match! One last thing, avoid mixing brand-to-brand if possible; otherwise you may have adhesion problems.