Question about Lenovo 0a36303

Lenovo T420 / 8 GB RAM / 256 GB SSD retrofitted / Win7-64 with Office 2010, normal office work in Word, Excel, PowerPoint or internet queries (no videos / downloads) around 4-5 hours. The original original equipment battery "original Lenovo" lasted up to 9 hours, but after 1/2 year was already "at the end" with 20% residual charge.

I needed the battery at work so that the T520 would last from morning to midday or midday to evening (approx. 4h)! Therefore, a large charger (Digitec 240294) is recommended.

The T420 also came with this battery, but I bought a second one to give me more "freedom".
It depends a lot on what I do with it. For office use only, 4/5 hours is certainly enough, but less for films/higher brightness.