If I have 3 metres on 1 side and I have 2 metres the other does it matter, does the sound shift? do I lose stereo imaging? or is it paranoia and I should quit worrying over it?

Your speaker cables would have to be different in length by about 200, odd meters to introduce ~0.001 second delay difference.

However, excessive lengths of wire FAR less can introduce RCL losses that can somewhat alter the Freq Response of the system. Probably still talking one or two hundred of feet of moderate gauge wire to do that.

In other words audiophile nerviosa

The longer a piece of speaker cables is, or the narrower its gauge, the greater its resistance. The greater resistance a speaker cable has the more power is lost between the amp and the speaker causing the speaker to play less loudly.
Therefore if you have a very short cable on one speaker and a very long cable on the other speaker, the speaker with the longer cable will be quieter.
It is therefore recommended that speaker cables should be the same gauge, the same length and as short as possible. However, unless the difference in cable length or gauge is substantial the difference in volume will be undetectable. Having said that, our hobby is all about achieving audio perfection, so the rule concerning the speaker cables gauge and its length is probably a good one to follow.

That's true, I cant hear a difference, but I keep reading that speaker cables must be the same length and I wonder why they all say it's so important.

With 4ohm speakers and 14awg cable, it would take a ~100ft difference in length to cause an audible difference in power (1dB). ~200ft for 8ohms.

Same for overall cable length. For 4ohm, there's no audible loss for lengths less than 100ft and 200ft for 8ohm at 14awg. 60/120ft for 16awg.

We do these strange things and end up with strange ideas because we strive for perfection, not because they make a difference!

if the cables where 2 miles, and 3 miles, it may make a difference, in yards, it does not matter. I moved from 3m to 15m cables, this allowed me to move the system from inbetween the speakers, to behind the listening seat. The sound of the system improved. Not because of cable length, but because it took all the boxes out of the way of the speakers.

Agreed ....a few yards wont be detectable matey

I'd notice a difference between differing brands, but the same cables at slightly differing lengths is a different kettle of fish.

Funny though ....when I bought 6 metres of NAIM speaker cable the salesman insisted on me buying two equal lengths !!
Not that I mean anything by that like as it were sorta thing ?

Due to the wifes orders, I had to increase the 2m length of one of my speakers to 5m, you know what?

Not a jot of difference, and if anyone tells you otherwise (at these lengths anyway) they are talking out of their rear ports!!

Ideally, if it can be helped, keep the lengths equal to be 'politically correct' as far as audiophile mentality goes.

But, as everyone here seem to agree, it won't make any difference if you didn't - that is, in a domestic environment. ( i.e. only a few meters of cable is used).

Many manufacturers, when designing their amplifiers, go out of their way to provide identical (symetrical) lengths of printed circuits, for the right and left channels.

In a world of millivolts or even microvolts, it's good practice to keep everything balanced, IMO.