A good mod can turn a clunky old game into one you’ll want to replay. The best free ones fix old problems first, but you still need your own copy of the game.

Where mods help

Engine rebuilds modernize a whole game. OpenMW is a free, open-source engine that re-creates the one behind the 2002 RPG Morrowind, adding modern fixes and supporting mods. You still need the original game’s data files, so it improves a game you own instead of replacing it.

Nexus Mods and Vortex cover many classics. Nexus Mods hosts mods for many games, including Skyrim, Fallout and The Witcher 3, and Vortex is its official mod manager, a tool that installs mods and tracks conflicts. A free account works, and Premium is optional, mainly for faster downloads and fewer ads.

Steam Workshop makes installing easy. For games that support it, you subscribe to a mod on the game’s Workshop page and Steam downloads it for you. It’s free to use, and if a game doesn’t show a button to browse the Workshop, it doesn’t support it.

Fixes for old PC games help too. Projects such as ThirteenAG’s Widescreen Fixes Pack and SilentPatch target older PC games, and download listings show versions for GTA and Need for Speed titles. These fix problems like stretched pictures and crashes instead of adding new content.

Where it falls short

Free mods vary in quality, and they can break when a game updates or when two mods change the same thing. A mod manager helps track conflicts, but it can’t promise stability. Back up your saves before modding, and add one mod at a time so you know what caused a problem.

Staying safe and fair

Download mods from the mod’s main page or a well-known site, and read recent comments first, since any file you download can be a risk. Publishers set their own rules. Rockstar, for example, says it generally won’t act against single-player, non-commercial PC mods but can change that position. For online games, check the game’s rules first, because modified files may be treated as cheating.

A good starting point

Pick a game you own that shows a Workshop button in Steam, subscribe to one well-rated mod, and play for a while. If you enjoy it, try Vortex for a bigger game.