At a certain acidity (around 5.5 pH), your teeth begin to demineralize.
This is why it’s commonly recommended that we wait for some time after a meal before brushing our teeth, so as to give our mouths time to return to a less acidic state so that we don’t lose enamel.
Here’s the thing:
If you decide to brush right after your meal tonight anyways, the negative impact isn’t obvious. Your teeth won’t exactly fall off.
In fact, the harm that comes with brushing right after a meal or the benefit that comes from waiting to brush on any given day is so incremental that they might as well be invisible.
Nevertheless, there is no question that the impact does become material and irreversible at some point in the future.
All else being equal, the person who waits at least 30 minutes after a meal before brushing their teeth is all but guaranteed to have healthier teeth 10 years from now compared to someone who always brushed right after eating.
The more immediate and obvious the consequences, the easier it is to act appropriately. Clearly seeing cars driving on either side of the road is a sufficient incentive 99% of the time to prevent a pedestrian from crossing.
The less immediate and obvious the consequences, the harder it is to act appropriately. Because the impact of brushing one’s teeth immediately versus later will not be obvious today, even someone with the best of intentions can be forgiven for wanting to ignore the above guidelines.
When a useful behavior does not have an immediate and obvious impact, you must learn to do it with the trust that you are accumulating “invisible” gains, and reducing “invisible” damage.