A nice tip I saw on youtube recently is to wind bobbins on your machine with the thread you're using; then transfer them to the serger/overlocker. You only need to wind a small amount - enough for the length of the seams. It's more economical than buying large spools, and also gets round the issue of colour matching.

Hi Mirco

I started using a serger a few months ago, and the advice I found online was to use white or black thread in the upper and lower loopers and thread that matched the fabric in the needle with the exposed seam.

After giving your comment some thought however, you might be onto something. A tailor could use specific colors for the upper and lower looper as well to create a signature of sorts. Just like the red soles of Jimmy Chew shoes, your garments might be purple and gold or yellow and green or...

The other thing I learned about sergers is the thread composition is as important as the quality. Some threads creat more lint in the machine than others, while a smooth consistently wound thread makes it easier to get the tension wheels set properly. Lumpy thread causes real problems.

Of course, if a lining is going to be used, it won't matter much.

Just a thought