This has probably been asked before, but I couldn't find the question:
Can one change his minhag to another, equally stringent, minhag (without doing hataras nedarim)? So for example: if one ties his tzitzis a certain way, can he change that style to a different way of tying tzitzis?
How "weak" would the minhag have to be? For example: the nusach one davens in is a hundreds-years-old minhag, and usually well sourced. Whereas wearing a black hat is much newer and (as far as I know) arbitrary. There is a wide spectrum of minhagim, (both between and beyond these two). Where would the line be drawn?
