There is no mandated minimum level of paid vacation time in the US. Most companies do offer some paid vacation time, but it varies from company to company (and even employee to employee, depending on negotiation skills).
As far as unpaid time off, culturally, the amount of paid vacation time you get at a company is assumed to be the maximum amount of time off you can take in the normal course of matters without putting your job at risk. Normally people only ask for unpaid time off if there's some exigent event that they have to take care of (health issues, family issues, etc.).
As far as unpaid time off, culturally, the amount of paid vacation time you get at a company is assumed to be the maximum amount of time off you can take in the normal course of matters without putting your job at risk. Normally people only ask for unpaid time off if there's some exigent event that they have to take care of (health issues, family issues, etc.).