If you want to know what your battery voltage is, if your charger is working correctly, if you built a shorted coil or one that is so low it's beyond the reasonable discharge rate of your batteries, then yeah a good meter is absolutely essential. But if you don't think it's relevant to expose batteries to dead shorts, don't care if a 0.2 ohm build is more than your battery of choice an handle, and think you can tell if you are running your batteries under voltage by feeling them - then no, you really don't need one.
Get a meter and get a good one. I've tried three of those crap meters from Harbor Freight Tools and none of them can give an accurate resistance reading below 20 ohms. That's 20 ohms - not 2.0 ohms. If you want to build sub ohm coils - hell anything lower than 2.0 ohms even - you can't use a $5.00 meter that may be off by as much as 40% high in that resistance range. Not one of the three I tried was even close to correct resistance readings.