I am not a real apple fanboy, but when I wanted a smaller laptop I had a few choices.
1. An business laptop from 3 or 4 years old that meets the build quality I want
2. A cheap Macbook Pro I found online.

I did not like the fact that it has only 8 GB ram, that’s also soldered on the motherboard, and I thought 128gb of disk space won’t be enough.
But I like the screen, the trackpad and the battery+overall build quality.

The 8GB of RAM is something I need to live with, but I found a way to upgrade the SSD much cheaper than buying an OWC or OEM one.

When your Macbook Pro already has Mac OS 10.13 High Sierra, this will work. If you are on one of the previous versions, you need an AHCI drive and things will be more complicated, so please before buying an NVME SSD, upgrade to High Sierra.

Step one:

-Make a Time Machine backup

-Buy a NVME SSD, I bought a 250GB Samsung Evo 960
(https://tweakers.net/pricewatch/587821/samsung-960-evo-250gb.html)

-Buy a Sintech adapter, I highly recommend the following adapter:
(http://eshop.sintech.cn/ngff-m2-pcie-ssd-card-as-2013-2014-2015-macbook-ssd-p-1229.html)

Firstly I bought the old style adapter, but it gave me some crashes and it puts more stress on the SSD’s PCB.

Step Two:

Use a Pentalobe P2 screwdriver to unscrew the back-cover of your Macbook Pro, make sure to watch the 2 screws that are close to the Macbook Pro inscription on your back cover, they are an other size. If you remove the back cover you will see the mainboard and the battery. If you have some kind of plastic spudger I would recommend to release the battery connector for safety.

Step three:

Remove the little torx screw from the original SSD, and pull it back. Do not pull it up!
And install the new SSD with adapter in your Macbook, and use the new screw you get with the Sintech adapter.

It will look like this, when installed.

Step four:

Unfortunately I do not have pictures from this step on, since I already had MacOS on the SSD since I made this tutorial when replacing the old style adapter. But it’s quite simple.

Screw the backcover on your Macbook again and when powering on Press command+option+R to boot up in internet recovery mode.
Go to disk utility to make sure your system recognizes the SSD, and format it (structure APFS, and GUID).

Restore your Time machine backup and boot up your system.

Step Five:

I sometimes had problems with my mac waking up.
And on this site :https://forums.macrumors.com/threads/upgrading-2013-2014-macbook-pro-ssd-to-m-2-nvme.2034976/page-25

Someone had the solution, start terminal and type:

sudo pmset -a hibernatemode 25

Other people use:

sudo pmset –g standby 0

But the last one did not work for me
More about hibernate settings : http://bendeegan.com/2016/04/19/how-to-make-a-mac-hibernate-properly-and-consistently/

 

Last but not least:
Please be cautious if you do not know what you are doing, and I am not responsible for any damage or lost data on your MacBook Pro if you follow this write-up