Expert opinion. If you came across unfamiliar indicator parameters in a book or online, be sure to find out how and why this indicator was used. Then you will be able to figure out why these particular parameters are used.
Expert opinion. In spite of the fact that, as a rule, natural parameters are selected, you should understand that small changes in large parameters do not affect the efficiency in any way. For example, experiments with changing the parameter from 120 to 121 will not be effective.
Expert opinion. If you experiment with the parameters yourself, keep an eye on the order of the numbers, and decrease and increase them proportionally. For example, you can experiment with the MACD parameter (24,48,24), but not with (52, 13, 98)