"I have measured out my life with coffee spoons." What is the author saying about the way that Prufrock has lived and is living his life?
This statement evokes careful precision: Prufrock rations his life in slight doses, not allowing himself joy or excesses. It speaks to monotonous repetition, particularly in the context of the preceding lines:
For I have known them all already, known
Have known the evenings, mornings, afternoons
Prufrock speaks both of constants—his life is allotted by coffee spoons—and of uncertainties: the “decisions and revisions which a minute will reverse.” One comes to understand that, for Prufrock, uncertainty is itself a constant.
There is an element of forethought, as well: "I have measured out my life" is ambiguous time-wise. Prufrock might be saying that he has already measured out his life in the past, but also that he has allotted even the future portions of his life—in other words, that he does not intend to change his habits.
Furthermore, coffee spoons symbolize the social rituals that Prufrock so dislikes: the “taking of a toast and tea” that obstructs any real conversation. Topics are bite-size and confined to suitable topics, not of the sort that Prufrock would prefer. He is a man who wanders narrow streets at dusk and sees a reflection of himself in the “lonely men in shirt-sleeves” who smoke pipes and lean out of windows—Prufrock must tire of the restraint, yet he too restricts himself.
The author is referring to the normal occurance of coffee or tea during social situations during the time period. When Prufrock says he has measured his life in coffee spoons, he is alluding that he has spent a lot of time participating in social coffee or tea. If his life can be measured in coffee spoons, then he has done little else to provide a unit of measure; he has spent much of his time simply being social. It is insinuated that he had little to contribute to these occasions. The image of a spoon makes a dull and not very enticing picture of how one's life has been spent.
I believe that the reference to coffee spoons means that Prufrock is living his life in carefully measured doses. He is not a man prone to extremes or one who would do anything out of the ordinary or unexpected; spontaniety is not his way of life.
Yes, coffee spoons can refer to the fact that he uses coffee spoons at all of the teas he has been to, but moreso it creates an image of one who is precise and exact--Prufrock would never just dump the sugar into his tea! Each and every decision he makes is carefully weighed and measured.
Measuring out life (so vast a thing) with a coffee spoon (so litle a quantity can be measured by that) denotes the enormosness of the task. In fact it undercuts Prufrock's prospect of securing any resolution about life what so ever. It also highlights the monotony - Prufrock believes - that is attached to the task of analysing or meditating on a life that a modern man like Prufrock has.