How to choose a high quality Birkin /Kelly?

1) Leather
For a good Birkin or Kelly the choice of leather is the most important point. The supreme leather has good elasticity and texture.
　
2) Stitch
For a good Birkin the leather stitch should be thick enough and each stitch should be inclined at a slight angle to the next (upper photo).
It should never be a thin stitch and should not be a straight stitch like
(see the second photos)

Poor stitch below (thin and straight stitch)

　
3) The Weight
　
Top Birkin is specially thinned with leather thinning machine so as to ensure that the Birkin will be light enough for you to take for a longer time without fatigue. Moreover, the softness of the Birkin can also be controlled.　
　
The weight of the good 35cm Birkin is 1090g, which is comparable to the genuine one 1100g.(Weight may change subject to different leather)

　
The bad Birkin may be much heavier since they are made without thinning procedure and choice of leather.
　
4) The hardware
High Quality Hardware is highly reflective and with smooth surface.
Besides, it uses good quality gold tone hardware of extra thickness (1 micron) of electro-plating. It can’t be rusting even over years.

　
On contrary, Some bad ones may look like below: Some sellers often use small photos to cover up the poor hardware (which can ruin your Birkin)

　
5) The interior
　
High quality Hermes bags have matching inside and outside.

Some Bad Birkin may have non-matching inside and outside color that may been
looking bizarre to some customer. (see below photos)
Also you can see the dirty oil stain inside.

　
Some may have very ugly interior (see below)

　 　
6) The handle
The handle of the high quality Kelly is skillfully made with round contour / curvature in the whole length
which unlike some bad ones which only can make it as flat doomed handle.
　
It is difficult to make because with 9mm thick the stitching require much higher craftsmanship than the flat one.　

　
Above and Below is the firm round handle of high quality Kelly and Birkin respectively.
You can see it is round in shape throughout the length of the handle.

　
But some of Kelly/ Birkin has flat handle like that below (especially thin at the end):
　

7) The handle structure.
Good Birkin is specially made with smooth and round contour ending to the bag so as to keep its good contour.The round shape of the handle is keep till the ending of the attachment.

While some of the bad replica may have flat handle ending to the bag or have bizarre attachment parts.


　
8) Firmness of the bottom
For a good Birkin it should stand up on the table with only the 4 pins touching the table.
(check below the good one for which you can see the gap between the table and our Birkin)

　
For which some bad Birkin may have soft bottom which leaves no gap between the table and the Birkin. See below

The reason is that they don't have a firm and hard enough bottom so that even with the pins below it cannot stand up on the table. (i.e. the pins is hiding inside the circumference of the handbag )
　

A soft bottom like this will even ruin your Birkin contour more if you put heavy things inside.
It is not difficult to imagine what will be the bottom like when you put heavy items inside.
　
9) Ergonomics
　
Good Birkin is skillfully made for your convenient use.
The zipper of the good Birkin is below the Flap so that you can take your items from it conveniently.
While some of the bad ones may have their zipper hidden below the flap so that you have to take the flap off first to use zipper pocket, very inconvenient.
　
It is a very important point as very often people will use Birkin in Open Status.
You need some safe pocket to hold your keys or other important items.

High quality Birkin (can access zipper conveniently )

Bad Birkin ( Zipper hide under Flap)
　 　
　
10) Structure
　
For a good Birkin the folding leather should be hiding inside the rim and not protruding out.
　

　
11) Ratio
The ratio of the height of the cover and the body as seen from the Birkin is 1:2 , which is the proper ratio for well accepted Birkin design.

12) Other Hidden Details
　
The key holder:
good ones have the thin genuine leather adhered inside.Some bad ones may have no inside leather

Rim oiling, Finishing, Rim coloring, Zipper, Contour.
　　
Conclusion
Always ask for enlarged photos of the Birkin/ Kelly if you are customers looking for details and quality.　
　
Some seller will use seemingly enlarged photos but with blur focus to cover the hardware and the stitch. One easy way to distinguish a good Birkin is to see an enlarged photos.
What I mean is really big photos which include the details of the Birkin.