Hi guys,
Just wondering how you deal with tolerances between objects in the modeling phase for stuff like box walls.

I'm modeling out a master for casting in urethane resin of a steampunk prop with around 17 individual parts. I've separated the parts for ease of casting, and hopefully ease of printing too.

When I started modeling, I snapped to the grid when creating my surfaces, but after I'd done most of the work, I realized that although many parts will be printed separately, I didn't leave any space between them so the printed parts will have no tolerances and probably not fit together properly.

I'm not expecting to print this on a pro SLA machine, so I'm wondering what you guys think - Do I need to go back and modify my object walls by 0.1~0.01 mm so they'll fit together, or is the accuracy of most desktop machines like the Replicator 2 or Ultimaker such that I needn't worry about adding tolerances?

Piccys for reference:
This is the issue: No gap between walls in spots in my model: tolerance_issue.jpg
For fun, this is what the final prop will look like: canary_mk2.1.jpg
This is a breakaway pose of all the proposed components. canary_mk2.1230.jpg
Some stuff is shown that won't be 3D printed, like the vacuum tubes (which I'm casting in clear resin) and the electronic components.