Print-on-demand platforms are designed to guide you through every step, which means a lot of sellers eventually walk into a conversation with a local print shop — for a bulk order, a specific finish POD can't offer, or just cheaper unit costs at volume — with no real sense of what that conversation is supposed to look like.
The first real difference is file format expectations. A local shop, especially one doing screen printing, will usually ask for a vector file (AI, EPS, or a clean SVG) with separated colors, not a flattened PNG. If your design was made purely as a raster illustration, be upfront about that early in the conversation — some shops can work with it via manual vectorization for an added fee, while others will ask you to source a vector version first.
Minimum order quantities are the next thing to understand before you get too far into a conversation. Screen printing in particular has real setup costs (creating the screens themselves), which is why most shops have a minimum order — often 12, 24, or 50 pieces depending on the shop — below which the per-unit cost becomes impractical. If you're testing a design and don't have confirmed demand for that volume yet, ask specifically whether they offer any lower-minimum digital printing options (like DTG) for smaller test runs.
Turnaround time is worth asking about directly rather than assuming — local shops often quote longer lead times than POD platforms because they're batching physical production runs, not printing on-demand one at a time. If you have an event or deadline in mind, say so upfront; most shops will tell you honestly whether your timeline is realistic rather than quietly missing it.
Always ask for and approve a physical proof before a full run begins, even if it adds a day or two — this is completely standard practice and any shop worth working with will offer it without hesitation. A proof catches sizing, placement, and color issues on a single unit rather than discovering them across fifty.
Lastly, don't be shy about asking for their file specification sheet directly — most established shops have one, and it removes the guesswork around resolution, color mode, and margin requirements before you've spent time preparing a file that turns out to be the wrong format entirely.