A grid is a tool for answering one question: how far is it from here to there? If your fight keeps asking that, use a grid. If it rarely does, a gridless map is easier to look at and easier to describe.
When gridded is better
A grid earns its place when position decides what happens.
- Area spells and effects. Cones, spheres, and lines are measured in feet, and on a grid each 5-foot square is one square on the map. Players can see exactly who is caught in the fireball.
- Movement and reach. Characters and monsters move in feet, and a grid makes it obvious who can reach whom without a tape measure.
- Cover and chokepoints. When a doorway or a pillar matters, a grid shows who is behind it.
- Tactical groups. Parties that enjoy puzzling out a battle will like the clarity.
When gridless is better
Gridless maps shine when the picture matters more than the measurement.
- Exploration and mood. A gridded cave looks like a game board. A gridless one looks like a cave.
- Narrative fights. If a fight runs on description, with cinematic movement and loose distances, you do not need to count squares.
- Speed. Without a grid, there is nothing to argue about. "It's about thirty feet" is a fine answer.
- Flexible scale. The same map can work for a small skirmish or a larger scene, because you decide what distance means.
How to decide for a given fight
Ask yourself whether anyone at the table will care about exact positions. If the answer is yes, the map needs a grid. If the answer is "maybe, a little," gridless with a quick estimate is usually faster.
It also depends on the table. A group that loves positioning and tactics will feel the lack of a grid, and a group that loves story will feel slowed down by one.
Switching between a virtual tabletop and the physical table
On a virtual tabletop, the grid is a layer you control. In Foundry VTT, a scene's Grid Type can be set to gridless, square, or hex, and the default square is 100 pixels. In Roll20, the standard square is 70 pixels, so a map is easiest to set up when its pixel size matches that. Because the grid is just a setting, a gridless map works well on a VTT: you can draw the grid on top whenever a fight needs it and turn it off when it does not.
If a map already has a grid drawn into the image, it needs to line up with your VTT's grid. Foundry has a Grid Alignment Tool for this. Otherwise, scale the image until the squares match.
At a physical table, a gridless printed map needs a little help. Print it at a known scale, and put a clear grid sheet or a dry-erase battle mat under it, or just agree that one inch is five feet and use a ruler when it matters.
Why the Goblin Mines bundle has both
The Goblin Mines Map Bundle comes with gridded and gridless versions of all six maps, because the right version depends on whether you are using a VTT or a printer, and on how tactical your fight is. If you are not sure which you will want, having both removes the decision.
If you want to print a map, see How to Size and Print a Battle Map at Home.