Professional suggestions on the best leather thickness for wallets, combined with different styles and usage requirements:

1. Short wallets (folded in half/trifold): outer leather thickness: 1.2mm–1.8mm
Too thin (<1.0mm) is easy to deform, too thick (>2.0mm) will appear bulky.
Inner leather/card slot thickness: 0.6mm–1.0mm
Too thick will cause bloating at the stacking part, it is recommended to thin the bottom of the card slot to less than 0.5mm.

2. Long wallets (accordion/zipper): outer leather thickness: 1.0mm–1.5mm
The overall thickness after folding needs to be considered for long wallets, and too thick outer leather will affect storage.
Inner layer structure: The card slot is recommended to be 0.6mm–0.8mm, and the thickness can be reduced with a thin lining (such as polypropylene).

3. Ultra-thin wallet (minimalist design) Overall thickness: ≤1.0mm
For example, the Tenuis TL wallet of the Japanese brand SOLAHANPU uses 0.6mm goat leather lining + 1.2mm Italian vegetable tanned cowhide, with a total thickness of only 6mm.

Notes:
Layer control: For each additional layer of card slot, the thickness needs to be reduced by 0.2mm-0.3mm to avoid the "brick feeling".
Process adaptation: Thin leather (<0.8mm) needs to use folding or hemming technology instead of traditional edge sealing.

Summary: The general solution is 1.2mm-1.5mm outer leather + 0.6mm-0.8mm inner leather, which needs to be adjusted according to the style and leather type (such as vegetable tanned leather is harder and sheepskin is softer).

Best Wallet Leather Recommendation:

• Full-Grain/Top-Grain: the most durable, retains the natural grain, the more you use it, the more texture.
• Vegetable-Tanned: environmentally friendly process, will change color over time, suitable for “skin” enthusiasts.
• Cordovan: High-end choice, extremely wear-resistant and unique luster, but the price is higher.

Suggestion: choose Top-Grain for daily use and vegetable tanned leather for personalized changes.

The lifespan of a quality leather wallet is usually:

Daily use: 5-10 years (head layer cowhide/vegetable tanned leather)
Careful maintenance: 10+ years (regular cleaning + care)
Top quality leather: 15 years + (e.g. horse rump leather / handmade customized models)

Key factors:
1. leather quality (genuine leather > synthetic leather)
2. frequency of use (avoid over stuffing)
3. Regular care (1 time per quarter maintenance)

Tip: The worn feeling after aging is rather the charm of a genuine leather wallet!

Perfect for! Leather wallets are a classic, practical and tasteful gift choice, especially suitable for the following occasions:

• Birthdays/anniversaries (symbolizing long-lasting companionship)
• Graduation/Employment (symbolizing wealth and maturity)
• Father's Day/Men's Day (practical and thoughtful)

Advantages as a gift.

1. Classic and timeless: wallet is a daily necessity, unlike electronic products that are easily obsolete.

High-quality leather will become more and more warm with use, becoming the “exclusive mark”. 

2. Tasteful: The material and branding of the wallet reflects the intention of the giver (e.g. crocodile leather/handmade leather goods are high-end). Can be customized engraved or embossed initials (such as initials), to increase the sense of exclusivity.

3. Practical: Compared to ties and perfumes, wallets are more frequently used.