Is there a difference in quality between 150 and 300 DPI?

There is an actual visible difference between 150 and 300 DPI, it’s important to keep in mind the printing method and the size your final work will be displayed at.
All-over printing: Even low-resolution files or files that were resized into a 150 DPI template, it seems really low quality in this print. This is why your designs need to have a 300 DPI file to not have a big impact on the quality of sublimation products.
DTG printing: Although 150 is okay, the smaller details there are, the higher the resolution should be. You may want to create these files at 300 DPI to ensure it prints nice and crisp.