--> For many sentences at least one, but often multiple of the above can apply to the sentence. Something might be a regular event, but it can also be a fact. Or, something is a habit that occurs regularly. There might be more than one reason to use the present simple.
The Present Simple is constructed in a sentence:
Using the full verb
Shit-rule --> he/she/it = verb + s
The Present Simple in a few examples:
I cook dinner every Friday.
As you can see, this happens regularly, namely every Friday. Since the subject is 'I', there's no need to add an 's' to the verb.
She eats turkey every year on Christmas eve.
This is a habit/tradition, which repeats itself every year (so, you could also say it's a regular event). Since the subject is 'she', we follow the 'shit-rule' and add an 's' to the verb.
The bus leaves every ten minutes.
It's scheduled, therefore regular. It's also a fact; not an opinion. Since the subject of this sentence is 'it', we follow the 'shit-rule' and add an 's' to the verb.
Sheila and her mom often collect money for a good cause.
This is a habit of two people, they think it's important to collect money. It also happens regularly. Since the subject of this sentence is 'they', there's no need to add an 's' to the verb.
You can use the Present Simple in three different kinds of sentences: