RE: deer cravin, buck jam and those that are simialar
They are useable all year, especially the mineral lick types. As to which flavor, that's pretty much trial and error. Certain flavors may work better at certain times, persimmon is a good example, because they're only available at certain times of year. A deer smelling persimmon in Summer will probably smell a rat as well. Corn is a fairly common smell throughout the year, but acorn isn't. You just have to try several scents and see what works best for the conditions.