I assist people throughout the day yet can be the cause of much distress.

I am generally quiet yet I do sometimes cause alarm.

I come in a variety of colours but black or white are the favourites.

I am ordinarily circular yet my shape changes according to interior fashion.

I hang around in the same place all day yet contain a number of moving parts.

I take my vigour from an external source but ration it out very slowly.

I have in recent years undergone a change in the way my insides function.

I am probably the most looked at yet least admired entity in the area.

I have a fulcrum harbouring three yet go up to four times that.

I am numbered up to over ten yet have five times that many ticks.

WHAT AM I?

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