Threads, to me are just a way to hold two pieces of fabric together, in all my years of sewing, the most important thing is the colour, whether it matches the fabric or contrasts.
I collect threads and have inherited a lot; I like old wooden reels and keep them when I’ve used up the thread. This is my small, old or vintage collection.
I like the labels – these reels are not used unless I need a particular colour and they’re kept in a drawer so they won’t degrade.
From the facts I’ve gathered, what thread goes with what fabric doesn’t matter when it’s just an everyday sewing machine but it matters with embroidery machines.
The thread type can also be important for different tasks and can make a difference to some sewing projects such as quilting.
Cotton is fine for most sewing jobs and is good for quilting where cotton fabrics are used. Polyester is what I use most but it can affect quilting fabrics over time, probably a cotton/polyester would be better.
There is nylon and rayon, but they can fail over time, and nylon can melt with a hot iron, they’d be alright for clothing but not quilting or anything that has to last, I’ve never used them, I did buy some nylon filament thread for transparency but it was awful to work with.
Threads (I have discovered) go by weight, a smaller number means it’s a heavier thread. The weight (wt.) of a thread has to do with the length of the thread, a thread is 40 wt. when 40 kilometres of thread weighs 1 kilogram and so forth.
Unfortunately, I have never found the thread weight written on a reel, that would make life much easier. I suppose the cheap thread I buy is 40wt., who knows, but it works just fine.
I went on a thread buying rampage a month or so ago and bought silk thread from India and a lot of top stitching, rainbow and embroidery threads, apart from the silk thread, there is no note of the composition but they sew well and were inexpensive to buy online.
I tried to put together samples of some threads I bought. I am looking forward to experimenting with all my new reels.