Quick Answer: The alterations with the best return are hems, sleeve length, waist suppression on trousers, side seams on shirts and dresses, and strap shortening. All five are cheap, quick, and permanently visible. The three to skip: shoulder alterations, shortening a jacket body, and anything on a heavily patterned or pleated garment - all three cost more than they return, and often more than the garment is worth. Budget roughly fifteen to twenty percent of a garment’s price for alterations and buy accordingly.

1. Trouser hems - the highest-return alteration there is

Nothing shows a bad fit faster than a wrong hem length. Two centimetres decides whether trousers look tailored or borrowed, and it is the cheapest fix on this list.

Hem for a specific shoe, and say which one. A hem set for flats will pool with heels and one set for heels will float above flats.

Consider two hems for a year-round trouser. One for flats and one for boots is the most-used alteration in most wardrobes that span two seasons.

Ask for the original hem finish where possible. A tailor can shorten from the top of the hem allowance and preserve a factory edge, which matters on anything topstitched.

Expect to pay very little and gain a lot. This is the alteration with the highest visible return per unit spent, by a wide margin.

And do it immediately on purchase. Unhemmed trousers get worn twice and then avoided, which is how good trousers quietly leave a wardrobe.

2. Sleeve length - the fastest tell on a jacket

A jacket sleeve should end at your wrist bone, showing about one centimetre of shirt cuff if you are wearing one.

Sleeve length is what makes a cheap jacket look expensive. It reads before fabric, before cut, before anything else a viewer notices.

Shortening from the cuff is straightforward on most jackets. It becomes more involved with working buttonholes, which is worth asking about before buying.

Shirt sleeves are equally worth doing and rarely done. A shirt cuff that covers half your hand undoes an otherwise well-fitting shirt.

Knitwear sleeves can be shortened too. A knitter can reattach a cuff, and on a good jumper it is entirely worth it.

And check the sleeve on everything before you buy. A sleeve you would need to alter is a cost, and it belongs in the price you are comparing.

3 and 4. Trouser waists and shirt side seams

3. Waist suppression on trousers. The gap at the back of the waistband is the most common trouser fit problem, and taking in the centre back seam solves it in one operation.

Buy for hip and thigh, then take in the waist. This is the correct order and it is how well-dressed people end up with trousers that fit everywhere.

It is cheap and almost always invisible. A centre-back adjustment on most trousers is one of the quickest jobs a tailor does.

4. Side seams on shirts and dresses. Taking in the side seams of a boxy shirt transforms it, and it costs a fraction of the shirt.

Shape the waist rather than reducing everything evenly. A gentle curve at the waist is what reads as tailored; taking the whole seam in straight just makes it smaller.

Both of these work best on plain fabrics. Stripes, checks, and prints have to be matched, which raises the price and the risk considerably.

5, 6 and 7. Straps, dress hems, and coat sleeves

5. Shortening straps. Camisole, dress, and bag straps are quick, cheap, and change how the whole garment sits.

A strap two centimetres too long drops the entire bodice. Shortening it raises the bust line and fixes what looks like a sizing problem.

6. Dress hems. Where a dress ends decides the proportion of the whole outfit, and a shop-bought length is rarely your best length.

Circle and bias-cut hems cost more. They require hand finishing and considerably more time, so ask before committing.

7. Coat sleeve length. A coat is worn over everything, so a wrong sleeve is visible on every outfit you own all winter.

Do it before the season, not during it. Tailors are busiest in October and November, and a September appointment costs the same and takes half as long.

And the three to skip: shoulders, jacket body length, and patterned garments. Shoulder alterations mean rebuilding a jacket, shortening a body ruins pocket and button proportions, and pattern matching multiplies both cost and risk.

How do you find a tailor and brief them properly?

Start with a dry cleaner that does alterations in-house. Work done on the premises is faster, cheaper, and easier to have corrected than anything sent away.

Test them on a hem before trusting them with a coat. A simple job reveals the quality of the finish, and it costs almost nothing to find out.

Wear the shoes and the underwear you will wear with the garment. A fitting in the wrong shoes produces the wrong hem, which is the most common reason an alteration disappoints.

Say what you want the garment to do, not just what to change. I want to wear this with boots gives a tailor more useful information than a number does.

Ask what they would not do. A good tailor will tell you when an alteration is not worth it, and that answer is worth more than the work itself.

Get a price before the pins go in. Alteration costs vary enormously by garment and fabric, and a lined or pleated piece can cost several times a plain one.

And take three or four things at once. A single trip with a small pile is how tailoring becomes a habit rather than an event you keep postponing.

FAQ: Tailoring in Your Thirties, Answered

What alterations are worth the money?

Hems, sleeve length, trouser waist suppression, side seams on shirts and dresses, and strap shortening. All are cheap, quick, and permanently visible.

What should I never bother altering?

Shoulders, jacket body length, and heavily patterned or pleated garments. All three cost more than they return.

How much should I budget for alterations?

Roughly fifteen to twenty percent of a garment’s price, and factor it in before you buy rather than after.

Where should a jacket sleeve end?

At your wrist bone, showing about a centimetre of shirt cuff. It is the fastest tell of whether a jacket fits.

Should I buy trousers for waist or hip?

Hip and thigh, then take in the waist. That order is why well-fitted trousers look the way they do.

When is the best time to get alterations done?

Before the season starts. Tailors are busiest in October and November, and a September appointment costs the same and turns around faster.

Is tailoring worth it on inexpensive clothes?

Often yes - a tailored inexpensive trouser outperforms an untailored expensive one. Fit is more visible than price.

TL;DR:

• Worth it: trouser hems, sleeve length, waist suppression, side seams, strap shortening, dress hems, coat sleeves.
• Skip: shoulder alterations, shortening a jacket body, anything heavily patterned or pleated.
• Hem for a named shoe, and consider two hems for a year-round trouser.
• Sleeve length is the fastest tell on a jacket - wrist bone, one centimetre of cuff.
• Buy trousers for hip and thigh, then take in the waist.
• Budget 15-20 percent of the price for alterations before you buy.
• Book before the season - October and November are the bottleneck.
• A tailored inexpensive piece beats an untailored expensive one, every time.