I do have a scale. It's a digital food scale. You can get them at pretty much any department store, they're pretty cheap.
I think its probably a good idea, but I wouldn't say you need to run out and get one right this second. I'm a pet-snake-owner, not a breeder or collector or anything like that. I weigh my snake maybe once every 6 weeks. She went a couple of months without eating recently and I monitored more closely during that time, but I'm not usually very diligent about it.
Everyone has their own way when it comes to record keeping and it probably depends on your personality and what your plans for your snake(s) is.
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