I’ve always scanned at the final resolution I needed it at, unless there were multiple destinations planned in which case I would scan at a resolution appropriate to the largest required size. No point in scanning more than you need to and using valuable time and resources in the process.
This can depend on the scanner. With my Coolscan V it takes the same time to scan at low resolution as it does at high resolution as the resizing is done post scan.
Also, if you scan it hi resolution you’ll never need to do it again.
I will be getting high res drum scans done for brochures & magazines so I just wanted to know if it was best to ask the lab to down size this file or scan again at a low res. Maybe there is not much difference? I just want to show the best quality I can on the web site.