True for many potent herbs, although cilantro seems to draw the most heat. My favorite use of cilantro (or any other herb) is to put a few leaves in the bottom of a bowl and pour hot soup over it. The fragrance is terrific and the flavor not so intense.
Most spices, indeed should be added at the beginning of cooking, as well as the “woody” herbs like thyme, rosemary, oregano, marjoram, etc. Other than pepper, I can’t think of a single spice I add late in the cooking, and pepper I add at the table. In fact, I can’t even think of a single recipe in which a spice is added at the end. The closest I can think of is the various spice dumps some cooks use in making Texas red (chili), but even those dumps are cooked out over a long period of time.
The delicate herbs like cilantro, basil, tarragon, parsley, and so forth, should almost always be added at the very end, as their flavor does not stand up to anything more than a short cook.
I just bought a very interesting Indian cookbook. It’s really neat for me to read because, although I enjoy eating Indian food at restaurants, I’ve never cooked any “authentic Indian cooking” myself (unless plain basmati rice and chicken in store-bought curry sauce counts 
).
In many of the recipes a tarka (tempering oil with spices) is added right at the end of cooking. The author of the cookbook explains that he differentiates between spices added at the beginning of cooking, and spices added later. I’ve only made a couple of the easiest dishes, but this seems to work pretty well.
For example, in most of his dal (lentil) dishes, the lentils are initially cooked with a couple spices (e.g. turmeric, cumin, sometimes garlic or cardamom). At the end of cooking, additional spices are fried in oil and added to the lentils. Common spices in the tempering oil are black mustard seeds, cumin seeds, dried red chiles, curry leaves, cayenne pepper, coriander seeds, and fennel seeds.
In the chapter on stir-fried vegetables, longer-cooking spices are added at the beginning (mustard seeds, fenugreek seeds, cinnamon stick, cardamom, cloves, peppercorns and cloves). Quicker cooking spices are added later (cumin and coriander seeds, whole dried red chiles, curry leaves). Ground spices may be added at the end, since they burn easier and heat can turn them bitter or mute their heat (cayenne, garam masala, rasam powder).
Curried meats and stews often start off with sauteing whole spices in oil, which infuses the flavor into the oil). Onion, garlic and/or ginger are added after the whole spices. Ground spices are added later in the cooking for a more immediate taste of the spices.
Anybody like Penzeys Spices as much as I do? They offer a wide selection of quality goods.
Supermarket spices are serviceable, but almost always stale and/or of lesser quality. I’m not the best cook in the world, but I use the best ingredients I can find, so it’s hard to screw up too badly. There aren’t any shortcuts. Even lowly pepper, which is a good spice, the supermarket variety just doesn’t compare to fresh ground tellicherry.
I like making my own recipes, basically cribbing certain ingredients from different recipes “Hey, that sounds good…” and intelligent substitution.
The problem with Penzey’s is that I tend to over-estimate the amount I need to order. It’s easier to just hit the “Ethnic” aisle at Stater’s and look for the little plastic bags of fresh spices. But I do order whole spices from them frequently. Alton Brown has got me hooked on grating my own fresh nutmeg, and the ones from Penzey’s are wonderful and reasonably cheap.
Mmm, Herbs and spices :)…
Used as fresh as possible, in the proper quantities and qualities, and added at the right time…you CAN learn to turn a mundane dish of peasant food into a magazine quality showpiece
Many have already said, throw out the spices in the bottles. Buy the freshest spices; herbs are mostly best used not dried, I mean green and fresh. If you used dried herbs you actually use less than with fresh just cut herbs.
A real chef trusts his palette and nose to lead him to the end.
You will learn grasshopper, keep asking questions…
Tsfr
p.s. I would add…Buy the Joy of cooking and a few other cook books that use and make complex dishes…read them like a text book,buy food magazines and read them, and enjoy your experiments… celebrate your triumphs.
But not the latest edition. It blows. Hit the used book store and get the 1973 edition. Priceless.
I should have mentioned Indian food as an exception to many of my rules (especially the “one herb accent” guideline.) 
It makes sense to add certain fragrant spices at the end of cooking, but flavoring spices I generally think of adding at the beginning. Also, adding spices to oil and then to the end of the dish is really different than what I’m advising against, which is adding spices directly to the dish. Some spices are oil- but not water-soluble, so adding them to a watery soup or stew at the end of cooking time doesn’t really do much for flavor. Paprika is notorious for this. If you decide thre’s not enough paprika in your goulash (or whatever) you cannot simply powder more paprika unto it with good results. You’re supposed to dissolve the paprika in hot oil or butter, cook it out for 30 seconds or so, and then dump the flavored oil into the dish.
Whole spices, cheap coffee grinder (or mortar and pestle if you have a masochistic bent). Ready-ground spices are great if you’re in a real rush, but whole spices freshly ground are another thing entirely. They seem to lose less of their essential oils/flavour when they’re left whole, and then this is all released at the moment of grinding. It’s a wonderful thing to grind some fresh cumin seeds and throw them into a jar of store-bought curry sauce or even spaghetti sauce.
[QUOTE=Common Tater]
Anybody like Penzeys Spices as much as I do? They offer a wide selection of quality goods.
I’m also fond of Penzey’s. Their website has lots of information on how to use spices & herbs. And there’s a store in Houston–where you can actually sniff before buying. But I do tend to
Another vote for looking askance at spices of a certain age. Some might last but most are probably past their prime. Sniff–do they have distinctive scents or are they just dusty?
ALSO another vote for Fresh Garlic rather than the powder. (Save the powdered garlic & onionsfor rubs.) And a word for Fresh Green Herbs. I’ve usually got a couple of fresh basils & chives in the garden. Dill in the spring.
“But I do tend to”…buy far more than I need. All that sniffing has an odd effect on the brain.
That’s a fine chest (of spices) you got there. 
I suggest you take the marjoram and the cumin out, then chuck the box of spices into the bottom far back of your freezer. Get a quality pepper grinder and find a local shop that sells a variety of fresh pepper corns. While you’re there, get a big-ass container of crushed or flaked sea salt.
Experiment with your cooking, but only use the sea salt. Try salting at different times in the process; for example high heat + fat + salt = poor man’s flash fry. Once you’ve got ahold of salt, put a pinch of marj and a dash of cumin in your palm and mix it up with your index finger, then breathe deeply. Add it to shrimp, scallop or fish sautee when the time seems right. (I don’t eat other meats anymore, but a good cut of beef, lean lamb or fresh chicken is generally the same.)
If in this process you get bored with the flavor, top your food lightly with some quality pepper.