If you hire employees you need to deduct taxes and give them a W-2
A 1099 is only used for independent contractors. While there is no specific definition of contractor or employee, a preponderance of the facts is most important.
In general, if someone works at your place of business and you direct them as to what to do and when to do it, this is an employee. Doesn't matter if the person is part-time or temporary worker.
Here is some good literature from the IRS that would assist you in making the determination between employee vs. independent contractor.