1mm each way maximum for new wheels. but I get them within 0.25mm each way.
there's also roundness and spoke tension to consider.
out of the three, equal spoke tension is most important.
it's totally up to the person working on the wheel if they want more attention to tension or trueness/roundness
This, and if getting it back under 1mm requires the tension to deviate more than 10%, it's time to consider a new rim and try to figure out what the heck I ran over.