You can get by with faster recovery one gear. I only have one rest day a week. I know some people won't at all. Just taking a random one here and there if something comes up. It's all personal preference and what works for you.
I switch up my routines every 6 weeks or so keep things new and fun and keep me motivated, as well as hitting the muscles with something new. I'll switch reps, lifting style, tempos everything to keep the Muscle shocked.