Following the earth shattering news last week that some mumsnetters don't own loo brushes, and what's more this isn't some oversight on the housekeeping front but a deliberate stance against "germy loo brushes dripping in the corner of the bathroom" (I'm too lazy to look up the exact quote paraphrasing), I have been keeping a watchful eye on the state of the Lawks household lavatories.
I removed the loo brush from the downstairs loo and left one in the upstairs loo (cf aforementioned rigorous scientific experiment). After a week the downstairs loo needed a jolly good scrub below the waterline. It also went through various mildly unpleasant phases which we won't go into but which would not have been necessary had a loo brush been available.
We have perfectly happy and healthy bowels, so no casting aspersions in that direction please.
I conclude that I don't understand how you can have sparkling clean loos without a regular scrub below the waterline.
I don't pretend to love my loo brush, and I change it often. But it's a necessary evil.