This week I had to replace the batteries in two of my laptops. My MacBook battery was 8 years old, and my Surface Book battery was 7 years old. Both of them were swollen, especially the MacBook one. I bought the batteries from iFixit.
Removing the MacBook battery was not too much trouble, because the battery was swollen so much – less than half hour or work. On the other hand, it took me several hours to detach the screen from the frame on my Surface Book. On that note, you should check out the Surface Pro 9 repair video release by Microsoft – Repair | Surface Pro 9. Battery attached via screws, screen is cold detached, and adhesive strips just peel off. Just awesome!
Regarding the batteries. I am quite happy – the one for the Surface Book is reported as just above the designed mAh capacity (original was 2387 mAh), and the one for the MacBook is reported as 9964 mAh (original was 8440 mAh). So, pretty good in my opinion. Also, happy with the batteries I bought from iFixit last year for my Pixel 3 and Pixel 3 XL phones.
My only concern now is to find a place which accepts and recycles LION batteries.