I don't. My vet has tried getting me to give Recon and now Patton a fourth. As long as the last comes on/after 15wks, I see no point. I wait a little longer between vaccines to make the last line up. Mom's immunity has certainly worn off and it should take. I've never had an issue. I see Legend got his at 14 wks and 6 days - I would not worry, personally. Lots of vets like to push this and I don't know why.
Danielle, owner of...
Fraggle Rock Collars
Fraggle Vom Richcreek CGC CA
Red Dog's Reconnaissance Man CGC
General Patton Vom Winter Storm