Making my own spindles has been rewarding to me in several ways. First, because I get to say I made it myself:) And then come the other advantages...
For me, it is less expensive because I use simple, inexpensive materials to make my spindles. It costs me no more than $2.00 to make a spindle.
But using inexpensive materials is only worthwhile if it doesn't take too much time and effort; so it's a good thing spindles are easy to make! Using a little sand paper to smooth things out, and a little tape (temporarily), I put together some pre-cut wooden dowels, wooden toy wheels, and cup hooks, and I'm good to go. I've even used bamboo skewers with washers:) I could leave out the cup hooks if I wanted to learn to spin without a hook, but I'm kind of partial to the hooks (after all, my first craft was crochet!).
Another advantage that comes along with my spindles being so inexpensive and easy to put together, I can have many spindles for little investment in time and money. At first I only set out to make multiple spindles because I wanted to try different whorl placement and weights... But then I realized that having more than one of the same size and type of spindle could be an advantage, particularly when it comes to multiple projects and plying... Plus, when I'm spinning, other people notice, and it's fun to be able to offer them their own spindle; I think it's natural to want to spin with others.
One of the best parts of making my own spindles is that I can move and remove the whorl whenever I want, and I do ... a lot! I spin mostly with a low-whorl, and since I choose to wind my cop into a center-pull ball, it's important that I be able to take the whorl off the spindle in order to take my center-pull ball of yarn off the spindle. I suppose that wouldn't be an issue if I didn't have a hook, but like I said, I prefer the hook:) A lot of people ply from spindles, or wind off into balls for plying, but that doesn't work for me. The simplest way to ply for me is from a center-pull ball, and rather than wind the cop on the spindle, then have to wind that cop off into a center-pull ball, I just spin and wind the center-pull ball as I go.
So there you have it, my reasons for making my own spindles:)