After fooling around with a Dell Dimension 4550, and a Dell Optiplex 210L, I am wondering how soon I will not be able to run a current and up to date Linux Distro such as Ubuntu, Mint, or Fedora on a Dell Inspiron 1520 with a Pentium Dual Core in it. I am currently running LinuxMint 17 Cinnamon LTS. Pretty much does anything I need to do such as browser with many tabs open and YouTube. Plays DVD's quite well. I am not interested in running Puppy, DSL, Xubuntu, LMDE , etc. I have older stuff I run those on. The reason I am asking is that I may consider more RAM or a Dual Core Duo upgrade If that's compatible with my chipset and BIOS ver, but not if the laptop will be antiquated in the near future.

While some of the more modern DE's are focusing on more intensive rendering, there are a lot of DE's focused on catering to lightweight systems. Mate and XFCE are two.
If you can currently run Cinnamon on 17, it probably won't be an issue anytime soon.
Even the ones focusing more on fancy effects, they are very efficient with their usage and - this isn't windows where it seems to try and use more resources every release to keep up with more eye candy effects.

You can generally run a linux of some kind. As time goes on we tend to make distro's larger and consume more resources. Luckily you will have support for that for years to come but you may not be able to run latest and greatest features. Someone will make a distro to keep that running for a decade or so.

I am only interested in knowing how far into the future I will be able to run a major Distro such as Ubuntu, etc. Not interested in running Linux of some kind on the 1520. I just want to avoid putting money into upgrades instead of something new if the 1520 wont run the latest greatest in the near future.

a major distro

i have ScientificLinux 6.6 running on a 14 year old DELL 8200
- pentum 4 CPU and a nvidia gforce2 mx 400 card

baring hardware failure Centos 6 is supported until 2020

use a LONG LIFE distro

forget about Fedora and ubuntu

CentOS or Debian stable or mint LTS

Hi,

You have not defined 'near future'. If you add memory to the system then the potential for use into the future will depend on the distribution you choose. Your caution is noted but we cannot tell you when the hardware will become obsolete. Jeremy called all our crystal balls back for being faulty so no way of envisioning the future.

You will have to be the decision maker about that longevity of the system since your needs may/will change in the future.

Then take a distro that you use now and see how far in future they claim they will provide support for. That will be your date.