If you've well upgraded your weapons and gear, you can be much more powerful and efficient, which will make your play-through much more enjoyable!
https://youtu.be/T6cYTD0jeso <<< Link to Video !
There are multiple timestamps to help you on what do you need !
Nice to know this is useful also for others !
I myself use it a lot. In my latest playthrough (now Legendary) I'm on day 6 with 2 tools and 2 weapons upgraded to level 6 ! This is fundamental is harvesting more efficiently, fighting with more strength, etc .... without it, you are simply wasting precious time and energy.
If you have some other topics you think it could be useful small guides like this one, please don't hesitate !