A digital weighing scale is a handy thing to have in your knitting kit. Most digital kitchen scales that work in 1g increments will suffice for the needs of most knitters. I actually have a small digital jewellery scale that works in increments of 1/10th of a gram, but I have had them for many years and long before I started knitting. They are, however, very handy as they are only 4×6″ in size and fit easily into my knitting bag.
Digital scales are inexpensive, and (if you have a set that you can also use in the kitchen) great for making cakes. A digital weighing scale is indispensable when making a pair of socks or mittens from a single skein of yarn. The popular Baktus scarf (which I am currently in the process of blocking) requires you to cast on only a few stitches, slowly increase along one edge until you have knit exactly half of your yarn, and then decrease along the same edge until you are back to your original cast on number of stitches and out of yarn. It’s a fantastic pattern for getting the most out of a single ball of yarn with no waste at the end, but guesswork as to when you have reached the halfway point of your ball of yarn could lead to tears and naughty words. You can pick up a pair of digital jewellery scales for about £7-8 on eBay, and you can find digital kitchen scales in any shop that sells kitchen equipment. If you want to test the kitchen scales out by making a cake, please feel free to send any baked goods to me and my cake-trained palette will be happy to tell you if your scales have resulted in baking success.