do number four in roman numerals must be always written as IIII instead of IV under any conditions

No, the number four in Roman numerals is not always written as "IIII" instead of "IV". The correct and standard way to represent the number four in Roman numerals is "IV".

"IIII" is not the recommended representation because it goes against the rules underlying Roman numerals, where a smaller numeral before a larger one indicates subtraction.

While it's true that "IIII" might occasionally be seen on older clocks or in certain regional practices, these are exceptions, not the norm. They deviate from the standard conventions for Roman numerals.

In virtually all formal, educational, and general contexts, you should use "IV" to represent the number four in Roman numerals. Resorting to "IIII" should be reserved for specific instances where it's part of a well-established local tradition or design choice. But even then, "IV" remains the universally accepted representation.

So, while there might be some exceptions, "IV" is almost always the right way to write the number four in Roman numerals. Relying on "IIII" under any condition is generally not advisable or standardized in the usage of Roman numerals.