Err..that's pretty unhygienic. Once you wash the Theraband with warm water and antibacterial soap, spread the band out wide and open and allow it to air dry. The plastic material will eventually start to lose the resin powder coating it came becomes slightly sticky. This is actually a blessing. That sticking feeling is to accomodate the higher friction connection between you and the upper wrap layer.
Theraband breaks down to an unusable level around 6 to 7 months in after too many wash and dry cycles. This is accounted for daily use and wash and dry cycle every day or two. Theraband is cheap. I bought a massive 20 meters roll for uses of all kind around the house as well, including tying my wife up with it. Kinky, yes.
If you washed up nice and clean before each routine, you don't have wash it after every routine. You can skip out after every 3 routines. But if you use it on an unwashed penis, well, it's hygienic to wash it after every routine. Bacteria is your worst enemy when it comes to abrassion and open wounds.