RE: How long do scents last?
That really depeneds on the product.
Some are good for a year and others are only good for one season only.
For example , those sent waffers from H. S. they will last forever as long as you put them back in its canister when your done with it.
As for that bottled stuff like Code Blue and Tinks 69 , those are good for one season.
As for the wicks your talking about , I wouldn't mix them too many oders on one wick might spook the animal.
Drippers like the from Wildlife Research can be mixed when making mock scrapes by using the product made for them like Active Scrape ,Doe Urine and Golden Estorus.
If and when you ever buy a product , read the the directions on how to properly use them.