I had an Eastpak backpack worth 100 euros from high school until recently (9 years) and all its zippers broke except for the 2 main compartments it has. I decided to invest in the same company as it seems to not skimp on its materials such as zippers, scratch-type pockets on the inside, and generally the fabrics it uses.

The 25L bag doesn't seem big at all at first glance, as if you have it slightly full or completely empty it looks like a 15-20L bag! I use it daily for the gym where obviously it comfortably fits a towel, 1L water, etc. Then I also think of having it for school since I don't have my laptop with me every day, so when I only need the basics like a notebook, A4 pad, power bank, 3-4 pens, a food container, and 1L water. For carrying the laptop, I have been using the Thule Accent for the last 3 years (https://www.skroutz.gr/s/13467864/Thule-Accent-%CE%A5%CF%86%CE%B1%CF%83%CE%BC%CE%AC%CF%84%CE%B9%CE%BD%CE%BF-%CE%A3%CE%B1%CE%BA%CE%AF%CE%B4%CE%B9%CE%BF-%CE%A0%CE%BB%CE%AC%CF%84%CE%B7%CF%82-Antitheft-%CE%9C%CE%B1%CF%8D%CF%81%CE%BF.html) which is 28L and much bulkier.

This specific bag can fit a laptop up to 15", however, I got it purely for the gym and school.