Depends on how long you're going to wait before you chop it. If the soil is dry and you want to wait a few more days before harvesting, water it. If she's dry on the day that you want to chop, don't worry about it.
I always chop after a full 12 hours of light. It's what works for me and i get good results. Don't get fooled by people telling you to put it in darkness for 2 days before you chop to "mAkE mORe TrIchOmEz." That's bro-science and doesn't do anything other than act as placebo. Science states that cannabis produces resin glands while photosynthesizing. Plants photosynthesize while the lights are ON. I'm actually going to start experimenting with giving high intensities of light to the plants for the last day it will be alive. Flipping back to 24 hour light, basically. I wonder if it will help push out the last few trichomes the plant was working on creating...
I hope this helps.
Happy Harvesting!