They aren't that difficult to recon yourself, you will need a pop tester, which as you say will be available for future use.
On the other hand, if you are busy, getting them done at an injection place isn't a fortune either, and they should do a good job, and have a good quality tester.
Down to personal circumstances, really. I wouldn't buy new ones unless the old ones are a real mess, broken bodies, etc.
I normally get injectors re-conditioned, BUT .... recently, I have found that the price difference between new outright and recon sometimes isn't that much, so it's a simple "value" decision for me now ....
I'll cheerfully buy tools too, but, as post #3 - even with how ever many tractors and disco's we have, and 100K mile service intervals, It'd sit in the shed for too long to bother, IMHO.