
Totally breed dependent. :) Like I said before, I'm pretty certain the whiteness of your breed is down to chalk rather than bathing. I'm not sure but I'd imagine your breed should not be bathed too frequently as the coat should surely not be soft? With my Papillons I bath them once a fortnight, always, with shampoo and conditioner. And always, always a day before the show. And if it rains or has got wet outside there's always a huge problem to keep them clean for even just a few hours! With my Malinois bathing the day before the show would ruin the coat, make it too soft and make them moult, so there I prefer several days before the show if not a week. But with them I only bath before Crufts and if they have got really dirty, so perhaps 2-3 times a year -a huge difference to every 14 days. :) Every breed is different. Same with my cats, the Persians have to be bathed 3 days before a show -anything more or less doesn't work -and the Exotics at least a week in advance. Coat quality matters so much. Your breeder should be able to advice you.
I looked up the main breed club and it has a series of grooming articles on their website, and it appears they have seminars in grooming as well.
http://www.wirefoxterrierassociation.co.uk/grooming1.html#(I have to chuckle every time I see your posts as my mind automatically reads WFT as WTF and it becomes something entirely different! Sorry, must have seen it used too many times on Facebook LOL.)