It would depend on your routine. If you sweat a lot from physical activities, it's going to be better if you shower more often, and vice-versa. I can go around 3 days without showering/bathing until I start smelling. But I would shower every two days, if my family wasn't 7 people (including myself). I used to be able to go without a bath or shower for a week when I was very young.
Sometimes, and only if you stink really bad, people may make a remark about you but say it in an indirect way, like maybe when they're near you they may say "urgh that smells" loudly, and who knows, they may not even be talking about you as they may not even know.
You should definitely be able to go without showering for 2/3 days depending on how hygienic you are and how active you are.
There is also the idea of having an efficient shower/bath. Do it quickly, and you waste less water.
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