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In a few of these recipes, I state that the sauce should be reduced, or cooked gently, until it thickens.
Careful and closely watched reduction and blending of a sauce can make all the difference to a dish which, in itself, may have required exacting measurements and preparation.
So, surely, as far as sauces are concerned, it is worth both time and trouble to stay in the kitchen and to cook the sauces cautiously without having to go off to attend to other household matters.
Two conclusions can be drawn from Alexandra Dumaine's remark that "exactness in cooking is difficult to achieve."
One is that the difficulty resides in achieving the exact required result, according to the precise indications in the recipe; the other, that you have to reckon with your own particular taste and that of the family, or of your guests.
We are not all born with uniform palates: you may like garlic, others may not; some prefer lemon juice, instead of vinegar, in the salad dressing, etc.
There must, therefore, remain a margin in the prescribed amount of herbs and seasoning to be used in the preparation of these dishes.

From "The Art of Simple French Cookery" by Alexander Watt
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