I didn't advocate sidewall plugs. What I can say is that properly fitted plugs in the tread can last a long time with little leakage and that three or four plu

I didn't advocate sidewall plugs. What I can say is that properly fitted plugs in the tread can last a long time with little leakage and that three or four plugs in the tyre tread (widely spaced, not all jammed in a big hole) seem to last a fair few years.