like not doing anything, just a spare laptop in case i ever need one, what if i use it years after i installed debian on it?? i would have to update like 300 packages and would take a lot??
You are not forced to update it.
even if you did, stable shouldn’t break itself regardless of how far out-of-date it is, nor will it upgrade to the next release without a little bit of hoop jumping first.
it is absolutely recommended to keep any system that has access to the internet up to date. i don’t know why people keep saying it isn’t
In my experience, the updates are quick as long as you boot it once every few months. I have a work laptop that I rarely use unless I’m travelling (I work primarily on a desktop, but I will keep it charged and update it once every 2-3 months so it’s ready for action.
If you let the laptop sit for years, the battery will be dead and there is a small chance that the SSD may be corrupted. They are only rated to retain data for a year without power.
Debian will have updates, but apart from the browser, it will typically only be security and bug fix updates.
The OS isn’t really the deciding factor here.
The thing is… The upgrade path degrades. Once one is 3 or more major versions behind, upgrading becomes technically challenging. (I have done this a few times…) It is better to just reinstall.
That said, a Debian system that works won’t just stop working. My Raspberry Pi 2 has no issues since the initial install.
Professionally, it is better to have a fast recovery path. PXE boot, Debian preseed, a config management system (Ansible, Puppet, etc) and local caches and you can be set in 10 minutes. (After years of setting all of that up.)