In the UK a ship was only licensed by the GPO to use two of those four available MF working frequencies. This was supposedly to ensure that there was a distribution of traffic on any particular working frequency but I fail to remember the reasoning behind this.
Of course many ships were able to use all the working frequencies but such use was outside the terms of the ship's radio licence. Some GPO surveyors were keen to insist that crystals for unlicensed frequencies were removed (this was even more stringently applied to the MF R/T frequencies, especially on fishing vessels) but most paid little attention.
The this caused a problem for ships spending time on the US Coast, where 448 kHz was a commonly requested/demanded working frequency by coast stations. Most such vessels carried a crystal for 448 kHz, either installed in the transmitter or secreted in a drawer.
Never regret growing older. It is a privilege denied to many. Don't worry about old age - it doesn't last.