One practice is more likely to eventually burn you than the other.

Please correct me if I'm wrong: The important point about choosing between "and/or" vs. "&&/||" involves their differences in precedence relative to other operators (especially the "comma operator"); the classic example (often seen in SoPW questions) being:

    open $fh, "<", $filename || die "oops!";   # should use "or" here
                       # (or else put parens around the args for the "
+open()" call)
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But the "burn" only happens when you use  &&/|| in a context where  and/or would be needed to do the right thing. In contrast, I can't think of any context appropriate for  &&/|| such that  and/or wouldn't serve equally well.

If you can find a context where  &&/|| produce an intended result and replacing them with  and/or produces a different (incorrect) result, that would be remarkably informative (and surprising, I think). NB: No fair making up obfu examples that depend on l-to-r vs. r-to-l differences -- people who get into that kind of trouble need other kinds of help and advice.

I'm guessing that BrowserUK has a similar view, and the reason we're both giving you grief about this is that you seem to be suggesting there are situations where using  and/or should be disfavored or unadvisable, whereas B and I would rather say that the better advice is "when in doubt, use  and/or" (which is what the OP seemed to be doing in the first place).