What leather goods would people be interested in right now?

[Tove09Tilda]

Oh, this is exactly my kind of question!
Certified business consultant here 😉

A/B testing is your best friend — whether online or at fairs.

How it works

Create a small batch of Product A (e.g., watch straps) and Product B (e.g., journal covers). Photograph both well.

On social media

If you use Meta Business Suite, you can even target different groups.
Show Product A to Group A, Product B to Group B.
Let the test run for a few days up to a month, then compare:

• likes

• comments

• link clicks

• profile visits

Whichever product generates stronger engagement is the better performer.
This method is often more reliable than fairs because the data is cleaner.

At fairs

Best if both fairs are in the same region.
Bring slightly different assortments each time — more of Product A at one fair, more of Product B at the next.
Compare:

• actual sales

• total revenue

• which product attracts more conversation or attention

You can A/B test pricing too

Announce Product A at Price X (production cost + 40% raw profit) to Group A, and Product A at Price Y (production cost + 56% raw profit) to Group B.
Check the same statistics as above plus any DMs or inquiries.
It’s an easy way to find your optimal price point.

Don’t forget the math

When you evaluate a product line, include:

• production time (based on average hourly wage in your area)

• material costs

• packaging

• share of workshop rent

• tool depreciation (please don't forget that! Most hobbiest do and it's simply undermining the value) 

• insurance

• booth fees (for fairs) + costs to get to fair (fuel etc.) 

• percentage of profit

• cost of storage 

Calculate how many units you must sell just to break even.
Then look at how realistic that number is within your usual sales cycle.
That alone often reveals whether a product line is worth pursuing. Despite that also consider if things can be bundled or cross sold,  e.g If a person buys a watch strap, do they buy a matching belt? If so - make a bundle (a watchstrap and a matching belt together for production cost plus 45% profit so slightly cheaper together in a bundle, than as two seperatly chosen products, also advertise it as a great deal (even if it's not)) or at least a cross sale offer (the belt is suggested when someone looks at watchstaps or simply place the somewhat matching belts close by at your booth, that they are in eyeside together). Selling is simple psychology and not magic or high profile science you need countless degrees for, make use of it! 

Hope I was of help,
Best
Tove