As others have said it depends on your attitude to risk / what you may lose, but distance is not the main concern.
Location, surroundings, and who may see you are more relevant than mileage, for some nearer home will have high risk while for others it will be certain locations, regardless of mileage.
Punting round the corner from your in laws is not safe because it is over 10 or 500 miles from home.
We know where immediate family and close friends live and work, but do you know where your OH's cousins or workmates that you have met occasionally live or work ?
One issue that almost caught me out was OH having friends and family (that I wasn't aware of ) who stayed opposite a well used WG flat, and who were aware it was a working flat. Some of them may have recognised me while I would have been blissfully unaware.