Hi Emma
welcome to the forum. It really is a personal choice as to whether it is worth getting a new machine or not. I have sewn with a number of machines and by far my favourite is my very first sewing machine I bought about 16 years ago. It has enough fancy stitches to keep me happy and has metal internal parts, but is also light enough to carry if I need to. It is also very forgiving no matter what I sew with it.
I also have a number of antique/vintage sewing singer machines that only do straight stitch. They are brilliant for quilting as they are heavy, all metal and do not wobble around. the stitch is always perfectly straight which is essential for quilting. I can service these ones myself.
My new machines (a couple of years old) are very plastic looking and sounding. They are much quieter and lighter but do not hold up to sewing bulky fabrics like the heavier machines with metal internal workings. They are lovely for basic sewing and embroidery on just a few layers, but hemming jeans are just frustrating.
If you decide to look for a new machine then I would recommend trying several different models out, with different fabrics/thicknesses to see what you prefer. A machine with metal internal parts will last far longer and be more forgiving than one with lots of plastic parts.
Good luck with whatever you decide.
Karryn
xx