For solid core cable on the reel, I do usually buy cheapest I can find, from a reasonably reputable supplier (say, the likes of screwfix or amazon), that claims conformance to the category I require (cat 5e or better is fine for domestic gigabit). The chances of lying about conformance is small, imho, so one cable reel is as good as another.
For made-up patch cables, I tend to look for branded names. Trouble is, even though the wires inside and twist rates might conform to category there is plenty of scope for manufacturing faults, and cheap and nasty RJ connectors that break. I have had a couple of Amazon cheapie patch cables that were DOA, no continuity on one of the wires when tested.
I seem to recall, when cabling my own home network, that the network adapters on most machines and OS's are capable of reporting how many bad checksums they've seen, though I can't remember off hand how you get at them. Once working I rarely saw numbers other than zero, even after running for days on end. Only exception was when a switch was slowly dying, and I saw error rates soar, which at least confirmed the counters do work.
The adapter on my windows XP, a Dell of about 8 years vintage, has a 'cable test' feature buried away somewhere in 'device manager'. It gives an indication of cable quality, and an estimate of distance to any fault. Again, proved useful when cabling my own, highlighted one dodgy IDC connection (my fault) that otherwise appeared to be working well.