the Jester
Legend
Do the "experiment" route too much, and it isn't magical anymore, either.
I disagree on this, but that's okay. Different strokes and all that.

Plus, if you are playing in a campaign with lots of low-level magic (potions of healing, +1 swords, etc.) then people ought to have an easier time identifying the common stuff.
Only if all +1 swords look like each other and look differently from +2 swords.
Also, it is a pain in the behind when you force "experimentation" on everything, and someone finds a weapon with an unknown plus. They don't even know what their total is, now! They way they are going to find out is make you tell them if they hit or miss until they happen to roll close and narrow it down. So why not just hand out that information the first time they swing in earnest?
Oh, I usually let them know after a few attacks in a real combat, though not through practice. You can't learn a magic weapon's plus without a real fight!
So let's say someone found a sword +1, +4 vs. women and children in my campaign. There might be some clue in its appearance ("the blade is etched with the image of an impaled baby"), but the pc wielding it might figure it for a simple +1 sword after their first combat with it. Only three sessions later, as the pcs attack a bandit camp (with plenty of female bandits!) does the sword's owner realize there is more to it.
This all helps keep some of the magical mystery of magic items mysterious and magical. You never know when you're going to discover that as-yet not unearthed property or power!
That said, I do favor things like History checks, sage consulting, etc. as additional ways to get clues, if not to outright identify, an item.
Some of the coolest items I've either had or seen in play were ones that the pcs in question never fully figured out. But that relies on a game that doesn't require constant item upgrades for the math to work.