I was wondering, what was the longest you have gone without watering? I am growing in soil in 5 gal. buckets. I am 2 weeks into flower. I watered when I turnded back the lights two weeks ago. During the first week, the buckets felt heavy, the top inch or so was loose and dry after mixing it with my hand, but pushing my finger down, I felt coolness, maybe dampness. At the end of the first week, they were still heavy, and the plants looked great, but I decied to water. Now the second week is over and they are still heavy, still looking good, Should I water? Should I wait until they droop to water again? I'm getting scared that the roots will get too wet. I have holes in the buckets and even after only a gallon of water, it bleeds out the bottom. So there is drainage. I have them up a bit, so there is air flow. I remember on my first grow that I went a week and half with out water once, then just watered out of fear, but the plants never looked droopy. Here they are last night, not watered yet: http://forum.grasscity.com/indoor-grow-journals/533374-2nd-grow-organic.html
Your 5 gal pots, are they like paint buckets? If so that's a fairly tall and narrow pot, which means it will retain moisture in the soil longer. I use 5 gal kitty litter buckets, very similar, and I can easily go a week between waterings. But don't worry what number anyone gives you, just go by the indicators from your own grow. Sounds like you got a good handle on that. If you're nervous about it, you can get a cheap moisture meter probe from Home Depot / Lowes / etc, poke that several inches deep into the soil and see if it reads moist or wet. For tall narrow pots you want to line the bottom with about 1 inch of rocks and be sure to mix plenty of perlite and/or clean sand into your soil mix for good drainage.
i start my babes in 2gal-3gal pots and then about 2 weeks before flowering i let them get pretty dry and i cut the bototm of the plastic around the whole thing and remove it. then i frill up the roots and put it into a 5 gal bucket half way full of dirt. that way i can water from the top and around the median area. it also may help mine dry up faster because i have to water every 3 days otherwise they start drooping. maybe since half the 5gallon bucket has a gap between itself and the other pot and the air might get into the lower soil to dry it up. anyhoo they are lookin great good job so far