The real difference is where the cost sits
Offset carries a setup cost and then prints very cheaply per piece. Digital has almost no setup and a higher cost per piece that barely falls with volume.
So the two lines cross. Below the crossover digital wins on price; above it offset wins, and keeps winning by more the larger the run gets. Where exactly that point sits depends on the job, which is why it is worth asking rather than assuming.
Offset wins on colour consistency across a long run
If a brand colour has to be identical on copy one and copy fifty thousand, offset with controlled colour is the answer. This matters most on packaging and labels, where copies sit next to each other on a shelf and any drift is visible.
Digital wins when every copy is different
Variable data - names, addresses, outlet details, numbering - is digital's real advantage, not just short runs. A dealer rollout where four hundred boards carry four hundred different names is a digital job even at volume.
Digital also wins on time, sometimes decisively
No plates means no plate-making. When a date is genuinely immovable and the run is moderate, digital can be the difference between material arriving and not arriving.
Plenty of jobs are both
A campaign can run its long common version on offset and its small district-specific versions on digital, and nobody downstream can tell. That is usually the cheapest answer for multi-version agri and dealer work.
Any printer who only offers one process will find a reason why your job suits it.
What to tell your printer
The quantity, whether the copies differ from each other, whether colour has to match existing stock, and the date. Those four answers decide the process, and any quote given without them is a guess dressed as a number.
Where the crossover actually sits
There is no universal number. The crossover moves with the size of the piece, the number of colours, the stock and how much finishing is involved. On a small, simple piece it can be surprisingly high; on a large, heavily finished one it can be low.
What is reliable is the shape: digital is flat, offset starts high and falls. Ask your printer to quote both for your specific job at two quantities and the crossover reveals itself immediately.
Quality is no longer the deciding factor it was
A decade ago the honest answer was that offset simply looked better. Today, for most commercial work, a good digital press is close enough that a client will not spot the difference on a leaflet or a short-run brochure.
Where offset still clearly wins is consistency across a very long run and certain specialist stocks and finishes. Choosing offset for a two-thousand-piece job on quality grounds alone is usually paying for something you will not see.
The hybrid case is more common than either pure case
Multi-version work - languages, districts, dealer names - is naturally hybrid. The common shell runs on offset where volume makes it cheap; the varying parts run digitally where variability is free.
If a printer has both processes under one roof they can split the job that way without a handover. If they only have one, expect the recommendation to match the equipment.
What this means for your brief
You do not need to specify the process. You need to specify the four things that decide it - quantity, whether copies differ, whether colour must match existing stock, and the date - and then let the printer justify their answer.
A printer who cannot explain why they chose a process for your job has not chosen it for your job.
