Allen Edmonds Sole Advice

I have two pairs of Allen Edmonds where a chunk has come out of the sole. The Drydens are older, from around 2011 (when Grapevinehill was still around), not worn as frequently. The Kenilworth was purchased in late November of last year. I have been rotating them and storing them with cedar shoe trees when not being worn. I generally walk about 3-5 miles a day in NYC. I sometimes get caught in the rain and don't have Swims yet. Is there something different I can do to keep this from happening, or is it just the way I walk? I was thinking of buying a pair of black Leeds from the seconds sale to wear out at night, but this issue is giving me second thoughts. Thanks in advance.

Allen Edmonds Sole Advice