Which "dry clean only" labels are real? I own four things I have never washed and they are starting to show it.

The line is not the label, it is fibre plus construction, and once you separate those two the four items sort themselves cleanly.

Fibre tells you whether the material survives water. Construction tells you whether the garment survives being wet, which is a different question: interfacing, padding, linings and structured shoulders can distort even when the outer fabric is perfectly washable.

Your four:

Silk blouse - hand washable. Unstructured, single layer. Cool water, a gentle detergent, no wringing, dry flat away from heat. Watch for dark or strongly dyed silk, which can bleed; test a hidden seam first.

Wool coat: depends entirely on construction, and yours is the risky one. Wool itself hand washes, but a tailored coat has interfacing and often padding, and those do not behave like the wool around them. This is the one that comes back the wrong shape. Most wool coats need airing and brushing far more than they need cleaning anyway.

Viscose dress - the actual trap. Viscose loses a lot of strength when wet and can shrink noticeably. It is the fibre most likely to punish you, and it is the one people assume is fine because it feels like cotton.

Lined blazer, leave it. Two fabrics with different shrinkage, plus structure. This is what dry cleaning exists for.

On the how, since "hand wash" covers a lot of technique and the failures are nearly all technique rather than fibre.

What actually felts wool is agitation plus temperature change, not water. So:

• Cool water throughout, and the same temperature for washing and rinsing. A cold rinse after warm water is what shocks the fibres.
• Do not rub, wring or swirl. Press it gently under the water and leave it. Movement is the enemy.
• Lift it out supported, not by one corner. A wet knit is heavy and will stretch out of shape under its own weight.
• Roll in a towel to remove water, then dry flat on another towel, reshaped to its measurements.

For the collar problem on the blouse specifically: you often do not need to wash the whole garment. Spot cleaning the collar and cuffs and airing the rest deals with most of what "not fresh" actually is, and it is far kinder to the fabric than repeated full washes.

General point that saves the most money: most things labelled dry clean need cleaning far less often than people wash comparable items. Airing overnight, brushing, and steaming does the majority of the work for wool and for anything tailored. Cleaning is for actual soiling. Over-cleaning a coat wears it out faster than wearing it does.

Where I draw the line, having got this wrong once: anything with interfacing, padding or a lining goes to the cleaner.

The reason is that you cannot see what you are risking. Interfacing is glued or stitched inside the collar, lapels and front edges, and when it gets wet the adhesive can let go in patches. What you get back is not a shrunken garment, it is a lapel with a bubbled, rippled surface that cannot be pressed out. It does not fail while it is wet, it fails as it dries, and by then there is nothing to do.

That is your blazer and quite possibly your coat.

Two other things worth knowing:

"Dry clean" and "dry clean only" are different labels. The first is a recommendation, the second is the manufacturer saying they tested it and it failed. Not a guarantee, but the distinction is real and it is worth looking at which one your items actually say.

Ask the cleaner rather than assuming. They will tell you honestly if something does not need doing, and many will do a press-only for much less than a full clean: which for a coat that has lost its crispness rather than got dirty is very often the actual fix, and it is a fraction of the price you have been postponing.