And floss too. If it's the evening, that's a perfect time to do it. If it's the morning, great time as well. Middle of the day? You've probably had food, brush them teeth. If you've recently (but not immediately after, wait a bit, drink some water) eaten, that's a perfect time to brush. Especially if you've recently had something sugary (avoid sugary stuff, also like I said not too recently).
And if you can, and haven't recently, see a dentist.
Your teeth are precious, and hard to replace. Lack of proper dental care can in many ways amount to a tax on the poor, where a lack of proper preventative care can turn mouths into an unaffordably fixable mess. Get people in your community to take care of their teeth too.
There's really only a few situations where you shouldn't be brushing your teeth right now: you vomited recently (brushing after vomiting can degrade the protective coating on your teeth), or you brushed recently.
Not having the equipment for it on you is only an excuse this once, carrying that stuff with you is a good idea. You eat and drink throughout the day, so you should brush and floss throughout the day. And who knows when you'll need to be presentable? You don't want to barrage your comrades, friends, partners, or "path to promotion" (your bosses) with bad breath.
You’re gonna damage your enamel if you brush that often. You do not have to brush every time you eat (unless you have a specific situation where a dentist advises you to, I guess).
Also, the concept of halitosis was popularized in order to advertise mouthwash
Interesting story about that, actually. A number of my family members just don't have enamel on their teeth (or only in some spots), some weird genetic thing (not erosion, just like that from the start). My baby teeth were like that, and also got quite fucked up for unrelated reasons. Then my adult teeth popped in, they had abnormally strong enamel (apparently something from the other side of the family). There were times where I didn't treat my teeth very well (common with addiction), and yet I've never had a cavity. I don't feel heat through my teeth, really at all.
I do however get excessive plaque, and am somewhat at risk for gum issues. That, along with my strong enamel, means that a few dental professionals have independently told me it's better for me to brush more often than others, and to be "less gentle". I also at one point had braces (messed up baby teeth carried over a little), and at that point in particular they told me to brush a lot (so there wouldn't be a color difference between what's under the brackets, and the rest).
So I brush three times a day, instead of the usual two. My post wasn't really my daily brushing routine, it was more begging people to brush a little (too many people don't). And to floss. And to go to the dentist (I know a guy who didn't go for two decades, until he finally got insurance that covered it. Wasn't the worst thing in the world, but also he had several cavities).
halitosis
It's not like it doesn't exist, though. And, more to the point, a lot of "bad breath" seems to have more to do with what they've eaten, than underlying medical condition. I mentioned that this was a call out elsewhere, so lets just say: please, please, please stop eating the stinky fish. At least it's not those Scandinavian ones that stink up all of everything, but it's still not pleasant.