For me, it depends on the specific rifle, load, and use. There are a few factors for consideration like whether the brass is near needing to be annealed, and the felt seating tension of load, before and after. If it is a whole batch that needs to be pulled and my use is for match, or LR hunting, I'll resize all of them to be sure the seating tension is consistent. If it's one or two, I'll just load them without resizing and note them for use as fouling shots. I have rarely, if ever seen much difference in groups at 100 or 200 hundred yards, but with some rifles/loads I have seen differences in ES with pulled brass that hasn't been resized. For serious work, I'll always opt for peace of mind. The other thing to note is the condition of pulled bullets, and whether they were in any way deformed during the removal process. IMO.