Itās entirely up to you, you donāt need testers but itās always good to double check the pattern to ensure its understandable to everyone
Thereās no min/max you can accept however many you want, something to consider is the Karma they have. Karma is a point system here on Ribblr that lets you know how many completed tests a user has done.
One point = one completed test
The only way to get karma points is when the designer clicks the gift and remove option so make sure to only click that option to the testers who follow the tester rules you place (they finish on the due, communicate, etc) You can see this number when they apply. Keep in mind newcomers and those that donāt test often will have 0 to no karma points at all
Also feel free to search the community or help center with any keywords you may have and also take a look at the testing guidelines as well for help as well, happy crafting and good luck with tester calls! 