You can make the task of hemming jeans a lot easier if you realize that the most important things to consider are your sewing machine needle and your thread, especially if you are attempting to recreate the original hem. You absolutely need to have the right kind of needle to get it to penetrate the fibers and multiple layers of denim.
You need to use denim needles, or the equivalent size(s) available in universal needles. In terms of your thread, you want to make sure that you don't just use the default thread that's available in your sewing and the sewing notions department.
The threads available for jeans come in a small selection of different colors from solid to variegated.You'll see here that we have a gold and we have a denim colors, but if you take your jeans with you to your fabric store when you're looking for this thread you realize that 95% of the time neither that neither of those two threads are the exact color that you need for your application.
You need to get the nearest match so that you can closely duplicate the manufacture’s stitching. You know - that is on the original jeans hem.
So my #1 recommendation before you even attempt to him your own jeans is to take your jeans with you to the store.
#2 is to grab a few spools in various colors of thread - including the ones that are meant for jeans.
#3 is to look to see which other threads are going to match your denim closely.
Question: are you trying to match the denim or the topstitching thread?
You can choose to match either color.
If you're using blue denim and you have a golden or brown stitched hem, you might find that it’s not even gold or even close to brown. But it's more in the olive range of threads in the threads display.
So - that’s it - take your jeans, buy the right needles, open up your thread spool and check to see which thread is going to match your jeans’ stitching the closest.
I know you'll be pleased with the results that you get when you don’t get bamboozled by the standard options of denim thread and when your machine doesn’t emit the sounds of terror - including the breaking of a needle.