Nope once you have voted a witness the vote remains until/unless you remove it. You get a total of 30 witness votes to use, so as you encounter witness projects that are doing good work in your estimation, vote them! I am one of the cofounders of c-squared, which is intended as an inclusive community for curators. As you find your feet here and start interacting with other users, keep us in mind - if you find a post by another author that you think deserves more love and upvotes, you can join us on Discord (link in the c-squared comment above) and request the "curator" role which will give you permission to drop off links you find by other authors. It will be a while before your own upvote carries any significant weight, but c-squared gives newer users an easy way to still be able to give a significant boost to posting you find and enjoy. Let me know if you any questions :) Cheers - Carl