I haven't competed solo in years and don't "need" dresses. Especially the pretty sparkly kind.
So now that that's on the table....like you I do sew. And I'm "re-learning" how to make skating dresses. And skirts. And going to start on pants soon. That's my story anyway, and I'm sticking with it. If I needed, and I wanted, I would just do whatever I saw fit. If I wanted to make a new dress and had time, I'm pretty sure I'd be like you and make one every year (or replace as I went, if I wound up not liking something). Crystalling looks like intense work, and the little I've done tells me that there is a learning curve. So that's a skill I'd want to learn, and tbh use as an excuse if I needed to.
If you have the skills, time and finances, and most importantly enjoy the process, why not make a new dress whenever you wanted?