It is the season of the Coronavirus and shelves at the supermarket are empty each day or you may be in a lockdown. So dry shampoo might be your best friend. Dry shampoo is just a spray on one.
Also people have just lost their jobs so saving water and money might be the way to go. Normal shampoo is about $6-$10 depending on the brand you buy.
I have some dry shampoo at home where I got it from the Liptember bag and kept it for a rainy day. You just apply it to dry clean hair and wella. You do need to comb through it or otherwise it will dry in clumps. And don’t spray too much. You don’t need to spray the whole can.