A FRIEND looks at the work I have done to decorate my apartment and shakes his head. "Why are you putting so much into it when you're never here?" he asks.

I will bore neither my friend nor the poor reader with a long discussion of the esthetics of paint and plaster. Just a short one.

The Japanese, after all, spent centuries developing a ceremony with which to serve tea. It should be obvious even to those who prefer coffee that attention to things we tend to consider inconsequential is more than mere embellishment. As one prominent Washington architect once put it, "Life is in the details."

So I see nothing wrong with pouring both money and effort into my humble residence -- almost ceremoniously -- even though my enjoyment of it (or the enjoyment it promises) is very brief during any particular day or week.

I say "boo" to this friend.

I must admit, however, that I began to seriously question myself when I hit the den. I had successfully patched and painted the rest of the apartment (all four rooms of it) before getting there, knowing full well I was putting the worst of the job till last.

In fact, I had no idea what problems lurked beneath the surface. Paint was peeling from both the walls and the ceiling. A spot of plaster over the hot water plumbing to the next-door bathroom was crumbling away as well.

With a sigh I picked up the paint scraper and dug in.

There is a certain perverse joy in scraping paint that literally flies at the touch of the scraper. The chips sing a song of rejuvenation, of tearing away the drabness of old things and replacing them with new life. But in this case, I was hearing not a song, but the Mormon Tabernacle. The paint fell away in great chunks, a surrender all the more pathetic because it was not total.

About three days later I took a moment to step back and view the carnage. On one wall the old paint (all four layers of it) had disappeared except for several inches around the edges and a large area in the center that approximated the shape of Mongolia. On the wall with the plumbing, cracks traced the paths of hot water pipes. On another, plaster had fallen out around the metal window casements. The ceiling looked like a victim of leprosy. Pock marks revealed places where plaster had simply fallen away from the rock lathing.

I had created a monster, and an ugly one at that.

For a time I felt my sanity threatened and considered calling the landlord. But, I thought, this is not how newspaper stories are written.

Many week-end home improvement artists ignore spots where paint has peeled and simply paint over it anew. I noticed this had been done several times in my den where the walls and ceiling were hopelessly mottled. Without tearing everything down to the plaster surface, there's nothing short of fixing it that will leave a respectable surface.

So I looked at the results of my scraping and wondered what "fixing it," in this case, might mean. Suicide? Too messy. Moving? Nowhere to go. Spackle?

Spackle! The marvelous material that goes in anywhere, spreads out tissue thin, sticks to almost anything and turns hard as plaster.

I was determined that this job was not going to fall on my head. So before spackling I put a coat of primer sealer over everything. Part of the problem in this room, I suspected, was that the walls had either been painted before they had completely cured (dried out) or were never properly prepared. This time they were sealed tight.

For the spackling I bought a cheap trowel (less than $3 at the hardware store) to cover broad areas. The idea is to spackle over the edges of the remaining paint, or feather them out with a long, swift stroke. The job requires several long, swift strokes eventually, of course. The first is merely a foundation, but you can fill in the cracks later.

The holes in the ceiling needed several layers of spackle. around the window I gouged the cracks as much as possible to make space for the spackle and remove loose pieces. Ditto on the hot-water-pipe cracks.

At first I hesitated applying plaster to places where the paint had not peeled, but looked like a tank had run over it because it had never been fixed when it did peel.In the end I spread some there, too, hoping it would hold. wIt did.

The worst job in creation is sanding. I knew this before I started. Sanding calls for a good, sturdy sanding block to hold the paper, a mask, safety glasses, a huge amount of stoicism and a healthy supply of liquid refreshment. The urge is to sand immediately after the first coat of spackle goes on, hoping that the sight of some progress will provide incentive to carry on.

It is better to leave this until all the little holes and cracks are filled, which may take several weekends of careful attention. Many times you will think about this as you sit in your chair smoking a cigarette while the clouds of spackle dust billow about you. These are called the "hunker and stare" times.

Finally I did sand it and, not taking any chances, primed it again. This naturally revealed a few more places demanding spackling, which I attended to and spot primed as well.

And when all the rough and gritty areas were finally smoothed away with a fine sand paper, when all the warts had vanished like heartburn in the night, I painted it. I painted it white, in long, victorious strokes, daring the least blemish to show itself.

Now, when I happen by, sometimes I stop at the den and turn on the light. I stick my head in and take a long, ceremonious look.