When using ZMA's do they have to be cycled or can you use it all year round to support healthy hormone levels?

If you feel like taking a day off, then do so, but those two are really needed for system replenishment, especially on high stress days, physical or mental. Best time, is prior to bed.

ZMA is good all the time. It is a quality, affordable supplement. I don't know about testosterone elevation, which is often claimed, but I certainly do sleep better and that is extremely valuable.

Below is an excerpt from the information about Bev ZMA from www.bodybuildingworld.com, you can click on Bev ZMA on the left hand side to read more.
An independent study of ZMA was recently conducted at Western Washington University under the direction of sports performance researcher, Lorrie Brilla, Ph.D. A group of 12 competitive NCAA football players who took ZMA nightly during an intensive 8 week spring training program had their total and free testosterone levels increase by 32.4% and 33.5%, respectively. In contrast, the placebo group of 15 athletes engaged in the same intense training regimen experienced a significant decrease in total and free testosterone by 10.2% and 10.5%, respectively. The insulin-like growth factor 1 (IGF-1) levels in the ZMA group increased by 3.6% compared to a substantial 21.5% decrease in the placebo group.

In addition to measuring the anabolic hormone increases in the football players, Dr. Brilla measured their muscle strength and functional power increases. The players who took ZMA nightly during the 8-week period of intensive training had 2.5 times greater strength gains than the placebo group. (1,2) According to Dr. Brilla, "This study shows that anabolic hormone and muscle strength increases can be induced in already strength-trained athletes by using a novel zinc-magnesium preparation". This is the exact formula used in BEV ZMA.
Pair this with the new Quadracarn that increases andorgen receptors and effectiveness, as well as a list of other great benefits, to achieve even better gains.

ZMA does nothing for me in regards to being a sleep aid. If anything, it keeps me wide awake. However, I like taking Bev's ZMA prior to a workout. Along with my other pre-workout supps, I feel a tremendous surge of strength when incorporating it in this fashion. I believe the magnesium aids in muscle contraction, and the zinc works synergistically with all the other anabolic substrates.