I take regularly to mean that you should be aware that it requires lubrication and a routine should be set up. I don't think the interval matters that much as long as the selected option isn't "Never". If it was that critical, I'd expect the instructions to be a bit more specific.
It depends on what it is, how often used and whether hot or cold conditions will have an adverse effect on it. The latter also determines which type of lubricant is used - high melting point grease, say, obviously is best for hot running conditions. What the devil IS this 'something' then? :o) TC.
Originally for some speed limits to be lawful repeater signs had to be erected at 200 yard intervals, I think it was, and everyone was getting off on technicalities because the distances were a few inches out.
The regulations now state that repeaters should be erected at 'regular' intervals. Very difficult to base a defence on irregular intervals if there is no definition of regular!