It all depends on the garment, how much of the shirt you are spraying and the pretreater. It’s like asking how many miles you can get with 100 gallons of gas.... some are economical some aren’t. Light shirts = less dark = more, thin shirt = less thicker shirt = more hoodie = even more, youth shirt, 3xl, left chest, half chest, full shirt, one sided or double, also some PT machines have a lot of waste, I hear some as much as a gall per 3 used and as low as no waste . I know this doesn’t really help but it really is an open ended question