Hey Kenman2,
There was a day when people harvested without having the loupe. Sure, it's a very helpful gadget. But it's not the end of the world if you don't have one. Here are some "harvest indicators" from The Cannabis Grow Bible. If these are in play, you're probably in the harvest window. Then you have to see how it smokes, and next time if you're growing the same strain you can pull a little earlier or later, depending on preference. Not all strains show all these indicators, so you need to get to know that plant a bit. But if you've got most of them in play, you're good to go.
1) 50 - 70 percent of the pistils have changed color (percentage depends on strain). And I will add that the pistils have receded back toward the bud. If you look at my avatar, that's Jillybean, and I'd say she's a 70-percenter
2) Plants have stopped producing crystals
3) Plants have stopped producing resin
4) Fan leaves and lower leaves have turned yellow and are dropping off
5) The smell has reached a peak
6) Buds have swollen, but then not increased in the past few days
Good luck!