I’m a maintenance noob. I wish to learn how to do my own oil + filter changes so I don’t have to drop 100 quid every time.
The manual for my bike (KTM 690 SM) gives me all sorts of nonsense about how many Newton Metres of Torque to tighten the screws to. Is this really that necessary? And if so, how the heck do I know how many Nm I have tightened to?
Use a torque wrench to tighten bolts to spec. Its advised but not essential. You should realise that fairing bolts should be barely more than finger tight. Best way to acheive this is with the appropriate bit in a screwdriver adapter.
The oil drain plug takes a few more Nm, but don’t swing on it, you just nipping it up to crush the copper seal between plug and sump.
Pair of pump grips for the filter, even more cheap and cheerful is to drive a sharp screwdriver through it and use it as a handle to loosen it.
Oil the rubber seal to the new filter before mounting it. K and N filters come with a handy nut welded to the end, so you can do it up with a spanner. Again, don’t overdo it, you’re only squeezing the o ring to make a seal.
Good luck 
You’ll know if you have over- or under-tightened the sump plug when your back wheel gives way for no apparent reason…
torque wrenches do come in useful for tightening wheel bolts etc.
Be very careful with oil filter cover, do it by hand without ratchet if you don’t have torque wrench! I think its only 6nm…
PM me your number will call you tomorrow and explain as its easy job, may help you first time if you not far from me possibly 
i like to tighten things to “tight enough so it wont fall off Nm of torque” with the exception of oil filters which get tightened to “really? that’s it huh? Nm of torque.”
For all maintenance noob needs
You don’t need a torque wrench if you know (can feel) how much
pressure to put on that tool to tighten it so it won’t come undone
and vibrate off.
Noob issues usually arise when over tightening things especially
small nuts and bolts or bolts in relatively soft alloy. Then it can
be a real pain either removing the sheared bolt / stud or worse
getting a stripped thread replaced in a crank case, which might
even mean replacing the crank case or engine.
So until you know exactly how hard to push on that spanner…
get a torque wrench 
or learn by trial and error and pay the price.
