Having never been asked the question before, two separate people approached me today to ask what the abbreviation YMMV means. While the less helpful might have choosen to answer by suggesting the inspired ‘Let me Google that for you‘, I’ll be more helpful and post the answer here for them and others.
While the abbreviation expands to ‘your mileage may vary’ (and has its origins in car advertising), the phrase means simply that ‘your experience may differ’ or in a looser form ‘in my opinion’.
A practical example is reviewing a gadget whereby the reviewer adds it as a disclaimer to what might be viewed as a subjective comment they have made based on their own experience, e.g. the hassle is worth it.