Help! Just how knackered is a knackered temp sending unit?

[Chuffy]

Hi guys - just done all the diagnostic tests on the cooling system to see what may be amiss with the temp guage on my Bros 400. The guage needle doesn't move further than a couple of milimetres away from the 'completely cold' zone, even when in heavy traffic, and I don't think the fan is cutting in either. The fan motor works. The temp guage works fine when the sender wire is earthed, and shoots up to "hot" as it should. But it occurred to me the temp sender may not be broken at all. How far should the needle go to register a normal working temperature? Half way round between Hot and Cold?

[LeftRightLeftThrottle]

My 650 always runs cold especially if its cooler than 70F. Even in the summer time it would only get up to halfway in traffic.

[HypnoToad]

My 400 can get up to 1/2 way up in the summer
Now in about 10 min its 1/8 the way up just from stop and go riding at
50° F

[NT696]

"Normal" temperature readout for my stock termostat shows 1/8" of black between the needle and the white 'C' area. I think Hawks usually indicate in the lower half of the gauge. The extra room above the normal area is to give you time to notice it, get off, and let it cool down before it turns into an aluminum puddle.
Like a lot of others, I also run a fan override switch that grounds the fan to let it run. I do this when approacing a traffic jam, or just tuning in the driveway.