NodeJs and Sequelize: when to sync?

I'm quite new to NodeJs but I was used to work with ORMs with PHP. Each time I deployed the site I did a sync to the database. Ex doctrine:schema:update --force when in Symfony.

However, in the documentation of Sequelize, they give examples where the sync is being done before each of the queries. Is this a good practice?

I just made a test and it's possible to make queries without the sync so I was wondering if it's a good idea make the sync only once when the application is launched. How do NodeJs developers are used to work?

In this example, I can do both:

User.sync().then(function () {
    return User.create({
        firstName: 'John',
        lastName: 'Hancock',
        locale: 'en'
    });
});

User.create({
    firstName: 'John',
    lastName: 'Hancock',
    locale: 'en'
});

The difference is that in the second case I'm not in a promise chain so I can't do a task that depends on the user creation without creating a promise on my own.

Thanks ;)

via unadivadantan