Yikes. In the US, federal law requires ...

There are some regulations in US federal law regarding working hours, breaks, and other conditions; but as also pointed out the main impact of federal law is on (minimum) wage and overtime pay - - - however - - -

The laws generally apply only to businesses doing business with the government in some way, and even then only to businesses above a certain size. They may be applied to businesses without government contracts if the size (number of employees) is sufficiently large.

Most states have additional "requirements" that apply more broadly than the federal ones, but in most cases they again apply only to companies with "state contracts" and/or above a certain size - typically 12 to 40 or so employees in a single workplace.

Additionally, a business is permitted to ignore the rules for overtime pay for "salaried exempt" employees, so that the rules do not apply to almost anyone paid a salary as opposed to an hourly wage. There are "lots of words" about who qualifies to be called "salaried exempt" but all the words are overridden by the provision that anyone who's salary exceeds a specific amount can be considered "exempt" and not subject to the rules. The last time I checked, the "specific amount" was about 80% of the federal poverty level income.

A second "out" for businesses is that anyone who's is eligible to receive "commissions" on work performed - rather than only an hourly wage - generally are exempted from the rules, even if they also receive a "base wage" and even if they never actually receive a "commission." ("Tips" from customers are (sometimes) treated as "commissions" but that gets pretty fuzzy in practice.)

An employment contract is about the only way to know what "they" can do to you, and about the only way to get a decent and clearly defined contract - and to have some assurance that the contract will be enforced - is to be in a decent union.

John