The longer the focal length and the wider the aperture of the lens , the MORE you should be calibrating your focus !

I have used several types of targets - but these days, this is my preferred "target" set up .........

3 cans ( 16 0z. preferred - full cans if it is windy- the idea being the cans represent a 3-d subject approximating a bird :-) ) with good details aligned at a 45 degree angle to the camera position. AF on a distant subject then AF on the center can and see if it is the sharpest in your magnified view - if one of the others is sharper, you deduce which way to make an adjustment and try again. For coarse adjustments the cans can be further apart and finer adjustments, closer together.

kcj, I personally think lens calibration is one of the most abused necessities. Yes calibration is a must to do good photography.
BUT, if you only shoot landscape at f16, why even bother? You'll never see it!
This is the homemade target I use for all my lenses and cameras.
Sometimes I find myself in the field with a new camera or lens that has no calibration. I just use a sign on a post or on a building that has lots of small lettering and focus on a letter in the middle. I've used a wall with texture and a piece of masking tape with a black line drawn in the middle of it. You need a place of high contrast for the focus to lock and You just need to be able to see where the camera is actually focused so you can adjust.
I don't recall ever using a tripod(always handheld) and a lens/camera usually takes about 5 minutes to do, and I guarantee you they are perfectly calibrated.
The X in the middle of my target is to assure my camera locks focus on THAT spot. The graduations are about 1/2" steps cut into the plywood. The target is about 12"x12". The angle is 45 degrees.
I wouldn't use anything that comes out of a printer unless it's on gloss foto paper. I use glossy magazine pages. They are sharp!
Good luck with your calibrating. Don't make it more than it needs to be!!!
SS