Can I Scotchgard my dog?

My West Highland White Terrier (Westie) gets really dirty when I take her out for walkies and I have to run her over with my Vax carpet cleaner at least every week. I was wondering if I could Scotchgard her to help keep her coat clean, and I also read this might make her less likely to catch fire. Would this shorten her life expectancy and if so would the pay-off in having her looking pristine be worth it?

Thank you so much for your help,
Geraldine