For regular customers that you can trust and they have paid on time in the past. Do what ever you want.
Thing is snow removal is a different animal then landscaping. Some people do them once they become regular customers. Some only want you when the snow is deeper then they are willing to do on their own with a shovel. So they are semi regulars.
The thing is I still get a lot of one timers for many reasons. These pay me cash when I get done.
Many a customer fears that they can hand you the money first you can just get into your truck and drive off. Also they don't want to pay until you are done to make sure that you did a good job.
Never meet a customer that made me nervous about being paid. Lucky that I never got burnt.