It's generally acknowledged that most of us on the forum prefer mechanical over quartz for reasons discussed and explored in great detail on other threads. Typically reasons of perceived complexity; all those tiny assembled parts working in harmony, romance and a connection with something 'craftsmanly' and with a noble heritage.
We all recognise the general inferiority of mechanical movements in terms of timekeeping accuracy; we accept that our $,000 watches aren't going to be quite as good at their basic timekeeping function as a $20 quartz and we're happy to live with that. We sacrifice outright accuracy for all the other tangible and intangible benefits that we see in a mechanical.
I have 3 mechanicals; An Omega Plant Ocean with the 8900 movement that is a fairly consistent ~+1.5s/day; a SpeedyPro which amazes me with a similar performance; and a Mühle Glashutte Teutonia II which is ~+7s. The two Omega's are, to my mind, excellently accurate and clearly within any of the recognised accuracy parameters (COSC etc.). The Mühle with its modified Sellita is at the upper end of my accuracy comfort zone. I think more than 10s out in a day (excepting real vintage pieces) would feel like real underperformance to me. 10s a day would be more than a minute out in a week and, while it might be a bit pedantic, I feel if my watch is showing the wrong minute then it's not really telling me the time properly.
I've just found myself on the HELM website looking at some watches after following another thread and they're pretty nice. I like the Vanatu but reading over the spec I noticed the accuracy: "-20 ~ +40 seconds per day". If I'm doing my sums right that's potentially -2 mins 20s or +6 mins 40s in a week. I realise that the Vanatu is a $275 unit so I wouldn't expect the performance to be COSC but that level of inaccuracy would drive my OCD over the edge in half a day! I'm not knocking the watch per se as we all pay our money and make our choice and we'll all have different priorities and values; it's just that that error potential would rule it out for me.
Made me wonder, how important is this to others? What's your accuracy 'tipping point'?