Thinking back over 16 years of sailing Tystie, The only time I was in serious danger of wrecking her was when I was single-handed, dragged the anchor and couldn't manage to be everywhere at once, doing everything at once. I couldn't be at the helm, getting her to weather against a fresh breeze, either by sail or under power, at the same time as being on the foredeck getting the anchor. As a direct result, I quickly installed an electric windlass with a switch back aft as well as one on the foredeck. Then I could motor gently into the wind, taking the strain off the cable, while electrically bringing in the cable. Now, I know it's possible to sail the anchor out, and be on the foredeck getting the cable in, while singlehanded, but I think it's a high-risk situation. Again, it's a question of having to be everywhere at once.
Apart from that, I think that going engineless is possible, but that safety and convenience are two sides of the same coin, or perhaps merge together at the middle of the spectrum would be a better way to put it. Making it into that difficult anchorage before dark, avoiding a night hove-to offshore in moderate weather is convenient; making it into harbour in the calm before the storm arrives is safer, rather than more convenient.
There were never any times when I was having difficulty sailing off a lee shore, and an engine was necessary for safety, though there were times when motor-sailing off a lee shore was quicker and more comfortable. There were times when a touch of motor was very convenient in getting through clapotis or windshadow, and it's difficult to say whether there was a higher proportion of safety or convenience in my judgement as I decided to turn the starter key.
All in all, James, I think you'll be doing the right thing in keeping a motor that's in working order, ready to go, but in avoiding using it as much as possible. JR is so much handier in tight anchorages, that it's possible to avoid the use of the motor more than with bermudan rig. At the same time, we have to recognise that most marinas ban sailing in and out, and some harbours have tight fairways where sailing is forbidden.