This is a tough one we get asked often..   What 'looks good' to your eye, may not 'look so good' to my eye.  It's all subjective, and these are simply suggestions (because we get asked frequently).  Every eye has a different way of evaluating output, and some are very critical.Standard original roll scans:  8" long on the shortest pixel side (for instance, 2400 pixels is 8 inches at created at 300 dots per inch.  From a 35mm negative.. an 8x12'' print is the largest we recommend...but we've printed larger prints that look fine--to my eye. Upgraded original roll scans:  16" long on the shortest pixel side. From a 35mm negative, a 16 x 24 is the largest we recommend.  Again.. we frequently print 24 x 36 prints from these files that look awesome.  Our advice:  start small--and work your way up from there.  Film has grain, and we love it; but remember the grain appears larger as the print size increases.  Additionally any softness is magnified as the magnification increases.