From “The Laws of Kashrus” by Rav Binyomin Forst” (pgs. 198-199)
The overwhelming majority of Poskim require that one wait six hours between meat and dairy. However, Sefardic and AShkenazic tradition differ in acceptance of the six-hour respite. According to Sefardic tradition, the six-hour respite is halachically required. It follows those opinions that interpret the Talmud in that manner. Ashkenazic tradition follows the lenient opinion in theory. Nevertheless, in practice, the six-hour respite was accepted almost universally among Ashkenazic Jews as well. Poskim declare that this is the proper conduch for anyone “imbued with the spirit of Torah”.
However, certain communities continued to follow the original Ashkenaic custom of reciting a brachah acharonah, waiting only one hour, and cleaning the mouth. This custom is found today among original Dutch Jews. Jews originating from Germany continue today their tradition of waiting three hours after eating meant.
This custom is perhaps based on the theory that during a short winter day the span between meals is shortened corresponding to the length of the day. Thus, the shorter waiting span should be sufficient at any time of the year.
While these customs are acceptable for one whose family tradition is such, others may not choose to follow these customs. The accepted tradition among the majority of Jews to wait six hours is binding upon everyone, unless his tradition is clearly otherwise. One who changes his custom to follow a more lenient custom is soundly censured by halachic authorities.