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.
+1 with Greyfox. If I pull any (we all make mistakes, better to pull it than chance it anytime), I 'feel' the way a new pill inserts into the case mouth by putting it in with my fingers. If it goes in easily (usually the case with multiple fitings and worked brass with little springback that is approaching the annealing stage, I use a NS die to 'tighten' the neck up (thats the only thing I use an NS die for btw).
When I say finger insertion, I don't mean inserting the pill all the way, I mean partially and that becimes an exercise in opinion, something that needs to be 'felt' by the person.
Keep in mind that all 90% of my rifle pills are boat tail and all my brass is VLD chamfered, so manual insertion will accor on all brass to a point.
To pull pills, I use a Lee 'Factory Crimp Die', run the pill into the die with the pill in the jaws (but not the brass) and run the jaws down on the pill and retract the ram. That pulls the pill handily and leaves no mark, like the Grip-n-Pull without the tool. I'm cheap.
Your prior bullets have already expanded necks to the tension you had. Newly seated bullets will still be gripped by that same tension. The seating force may be less, as now you're not upsizing with new bullets like prior bullets. That work is already done.