I love my 34c. It was my first “good” razor but in about two years the retaining ring that holds the knob in place has loosened twice and the knob fell out. The razor has a pretty cush life. Always in a case and only used when I travel. Is this a thing? My 37c which gets regular use at the sink has never had the issue. I have fixed it both times but wonder if there are more reliable options.