I was at my mothers house last week looking through a bag of lightly used clothing that she had been given and came across a nearly new pair of jeans which didn't fit anyone in my house. Thinking they were too good to throw out, I thought I would have a go at downsizing them for youngest son. I was a little apprehensive about sewing denim as my previous attempts had been frustrating, even though successful and wondered how my Janome would handle the thickness. I settled on a plan of attack which involved unpicking the waistband, belt tabs and zip for reusing and cutting out new backs and fronts from the existing backs and fronts, leaving the back pockets and yoke in place. I used a pattern that I had used previously some years ago for my daughter which I had drafted from a Topkids book and since my son would only wear skinny jeans, added some length to the legs to match some existing jeans he already had. I then made a trip to my favourite fabric shop and matched the topstitching on the existing jeans with a roll of jean topstitching thread which set me back $3.80. The lady in the shop said not to use it in the bobbin and don't lock stitch as the machine won't like it (I found this to be true and just tied the ends). I put buttonholes in the waistband on the inside and raided a pair of too small shorts for the buttom up adjustable elastic which I put through the waistband for a custom fit.
I am really please with the end result as is my son and don't think I would change a thing if I did this again, which I am quite keen to do.