In the end you would want to silkscreen if you want to produce any kind of print in large quantities. Although vinyl prints will last years, a silkscreened graphic will last as long as the garment. Unless the graphic is too complicated, it could only take minutes to cut the vinyl, and seconds to heat press the graphic to a tee. Overall it’s a quick process for just a few prints. When silkscreening, creating the screen for a particular graphic is going to take hours, but once the screen is made, printing each tee is going happen in seconds. Also, you can only do vector graphics with vinyl print, such as text and simple graphics. The more complicated the graphic gets, the longer it’s going to take to weed out the negative from the vinyl after it’s printed. The only time you would use vinyl would be for samples, or where individual prints are unique. If you’re making t-shirts for your basketball team, You would silkscreen the team name and logo, and you would heat press vinyl the names and the numbers on the back.
This is from a popup by Off-white at Tokyo. Same graphic was already silkscreened in multiple shirts, and they heat pressed individual numbers in cut vinyls at the actual pop-up:
If you want to find out more about the difference, Hypebeast explains the process in 2 videos:
If you want to find out even more, you can take a class. In the summer of 2017, I took a continuing education class at SVA. It costed $640 for a 2 months program where you come in once a week for 3.5 hours. The class started at 6:00pm and ended at 9:30pm, so most of the people taking the class had day jobs. It was diverse community with directors, graphic designers, curators, people who were interested in silkscreening. L. Wright, who had clients such as Andy Warhol taught the class. They teach the whole process for the first 2-3 classes, and rest of the classes are getting your hands dirty and you can come in during the weekends and lab hours to print whatever you want. For me it was Cam’ron