Will the caffeine effect wear off?

Yes, like most drugs, you build a tolerance.

I tend to build a tolerance within a few weeks, to the point that I barely feel it. I then go very low-caf for awhile (I seem to feel that I’ll Simply Die if I don’t have any (Die! I tell you I’ll just Die!) a d then one day go back to full cat and become very productive again for awhile.

I’ve just been reading that caffeinated coffee is good for your health although I also usually avoid it too because it jumps me up. I do have one diet soda around mid-day. If I drink more particularly after about 3 p.m., I won’t sleep.

Yes it will eventually if you continue consuming it daily.
It might have been a placebo effect too, psychologically you were expecting to feel ramped up so you did, or at least more than maybe the effects of the one large cup. I drink 3–5 cups of coffee every morning between about 7 and 9 a.m., the effect wears off by mid-morning and I know I have a tolerance, except, I too cannot drink any caffeine, minus the occasional diet soda, late in the day or I will be up all night too.
Last winter I got a mocha one evening around 5pm, just sounded so good, I was up all night, horrible, never again. haha

I used to drink the half caff blend forever, think I might switch back because I love the whole sensual experience of coffee most, the smell, taste, warmth, and the caffeine is a side effect though like @canidmajor says, if I don’t get my coffee I feel like I will just die!
The half caff is great because you can linger with an extra cup or two and not consume too much caffeine. I had to do a fasting blood test a couple weeks ago and I took my giant insulted mug of coffee in the car with me to the lab at 7 a.m. Just knowing it was waiting for me got me through the horrible no coffee moment.

I got back to my car and just sat in the parking lot savoring my reward. lol

Don’t do it every day. Alternate between caffeinated days and decaf days. That will reduce the chance of your body building a tolerance.
Warning. If you do it everyday for two weeks and then skip a day you will get a caffeine withdrawal headache.
Alternate days and that will not happen.

I’d say you will still feel more energetic with the caffeine than without, even on a regular basis, but you will certainly build a tolerance and then when you don’t have your caffeine you will suffer. Most people suffer, there seems to be a few who don’t. Withdrawal usually involves feeling under the weather (some describe it as feeling as though they are coming down with something) headache, and wanting to go to sleep.

Caffeine is great at fighting the sleepy feeling, although people addicted to caffeine typically sleep just as well as non caffeinated people.

My feeling is it’s best to drink it daily or not at all. Why put your body through the withdrawal trauma? A little cheat here and there, yeah ok. But, days or weeks at a time and then withdraw for months and them start up again? That’s what I think is a bad idea.

Even three days of a lot of caffeine (say two cups of coffee equivalent) I will feel the withdrawal and everyone will tell me I look terrible. When I cheat it’s usually one cup of tea or one can of soda.

As a side note, my observation is people who quit caffeine begin eating much more chocolate. It’s like the body will suck every morsel of caffeine it can get, even if we don’t consciously realize we are craving caffeinated foods.

I don’t get the coffee love affair thing. If I drink any, it’s only about ½ a cup. Any more than that and I just feel all jittery, and it’s uncomfortable.