Step 22 = Consider a washable doormat.
Doormats work hard to trap dirt and moisture. But you need to keep your door mat clean, so it doesn't become a source of grime itself.
A good hoover, with the hoover nozzle, will remove loose debris each week.
A machine washable doormat means that you can deal with the inevitable dog-poo-on-shoe incidents with ease.
Marvel Mats (available from Dunelm) are machine washable at 30 C, so if you add Dettol Antibacterial Laundry Sanitiser to your wash (which works at 30 C), along with your usual detergent, then you will know that the mat has been disinfected. *Edit* *Before washing a doormat, make sure that you hoover it very well and hang it up outside to beat any residual dust out of it - washing a particularly grimy mat without properly completing these steps led to an expensive blocked-washing-machine-filter incident!*
It is a good idea to buy two washable doormats, as they do take a while to dry once washed. So you can have one in use and one being washed / dried. You may find that you like the convenience of them so much that you buy some to place at your back door too...