Parts are never printed individually, and operators choose model orientations for each
run to maximize loading (while avoiding cases known to lead to unacceptable "stair-stepping"
or print lines on surfaces). This is a recurring gripe of artists and modelers here in the forum, and
there have been promises to include user-defined print orientation in the workflow at a later time.
Still, if your model absolutely requires _reproducible_ sub-millimeter precision, additive manufacturing
as a service on a per-piece basis may not be adequate - sintered materials are more or less "spongy"
on the micron scale, and individual pieces may be built on different printers, perhaps even by different
sub-contractors. Conventional plastics manufacturing on the other hand involves moulds machined to
high precisions and constantly monitored for wear, which is why it is economical only for large numbers.