bladder flushing

i may have a uti took urine sample today my urologist assistant asked how often i flushed my bladder ive never flushed my bladder i just cath every 4 hours or so does anyone know about this flushing bladder

ive been injured 15 years and none of my docs has ever brought it up she said its good for not getting utis and getting rid of them but i rarely get them

thanks for any input

bladder flushing