Depends. If it is a conscious technical experiment, I keep it as a reminder of misapplied settings or of equipment limitations (eg, testing lens for coma, flare, etc). If nature photography featuring a specific organism, I keep technically bad shots that show interesting behavior, or boring shots showing anatomic feature well (bird species get 1 good "butt shot" for record of tail plumage; leaf and stem arrangement on wildflower, in addition to the actual flower, for aid in identification), or ecology of location of the organism, or just a site shot with coordinates (for returning to site later).
I weed out "near-duplicates" a lot. Freehand shooting of birds, freehand close-ups, any macro when a breeze is blowing - there will be a bunch of similar not-technically-ideal shots. Out they go, unless there is something interesting in the not-technically-ideal shot that I might want to follow up (what's that pollinator insect on the wildflower).
If I didn't do rapid rough cuts, I would be swamped. Back up "all" on one drive, just in order to have two copies (computer drive and back up drive) and clear the cards. I flag rejects in Lightroom on a quick first pass. Then I check my flagged shots again, and pitch. At least 50% of shots are gone. The remainder get more thoughtful evaluation, and I am not in a big hurry to ditch.
There's a dandy phone photo app called "Theodolite", gives you compass info (altitude, azimuth, elevation), time, date embedded into photo. The main use is for landscape shot planning. I may see an interesting location at an uninteresting time of day. What would it look like with Milky Way in background? or how would sun hit it at a particular time of day and date? Easier to take the phone snapshot than record manually using physical compass and gps.