Disclaimer
Work schedules are up to an employer to set and enforce, i.e., scheduling of employees is entirely within the employer's control, and it is up to the employees to comply with the schedule that is given to them.
With only extremely narrow exceptions relating to certain regulated industries or collective bargaining agreements, adults, as well as youths ages 16 or 17, may work, and/or may be required to work, unlimited hours each day (the only limits are employee morale, practical realities, and common sense in general).
Employers can require employees to work overtime, as long as the non-exempt employees are properly paid for the overtime hours they put in (keep in mind that neither Texas nor federal law require payment of "daily overtime" - overtime pay at time and a half is owed only for hours in excess of 40 in a seven-day workweek); for details on overtime hours and pay, see "Determining Hours Worked for Non-Exempt Employees" and "Calculating Overtime Pay" in this book.
Under the employment at will doctrine, an employer can change an employee's hours with or without notice.
No Texas or federal law requires advance notice of overtime or schedule changes, but as with most employee relations matters, it is a good idea to give as much advance notice as possible when informing employees of extra work or changes in their hours; sudden and adverse changes in hours, or burdensome overtime requirements announced with little or no notice, can under some circumstances amount to good cause connected with the work for an employee to resign, resulting in potential unemployment insurance eligibility for the employee who resigned. Any such employee would have the burden of proving that a reasonable employee would have resigned under the circumstances, and in addition would have to show that they gave reasonable notice to the employer that they were so dissatisfied over the schedule change that they were considering resigning from the company.
Although some states require what is known as "show-up pay" (a minimum amount that is paid to employees who show up for work, only to be sent home early or with no work at all), no Texas or federal law requires such a payment; however, it is best to express the employer's policy on that issue clearly in a written policy, one way or the other.
For a sample policy regarding work schedules and compliance with company timekeeping procedures, click here.