The useful question here is not "what condition is it in" but "will it do the job".
The questions
"What is the specification?" Bat size and weight, racket grip size and weight, shoe size measured inside, plate bore diameter. These decide whether you can use it at all. Non-answer: the brand name again.
"Has anything been repaired or replaced?" Re-gripping, re-stringing, toe guards, re-glued soles, replaced bearings. None is a problem; an undeclared one is.
"Can you flex it, turn it, or work it on camera?" Thirty seconds of the thing behaving like itself.
"Any cracks at all?" A cracked frame is a dead racket. A structurally damaged bat is a parts item. Ask directly.
"When was it last strung or serviced?" Tension drops with time whatever anyone does.
"Can you weigh it?" Stated weights are frequently the label's rather than the item's.
"Is there a smell, and has it been cleaned?" For shoes and anything worn, this is the most common reason for a return.
What protection covers
A specification materially wrong, an undeclared repair, damage not shown, a different model: seven days from delivery. Normal wear that was described is not.
Questions people ask
Is second-hand gear worth it?
Very often, especially for growing children. Buy on specification, not looks.
How old is too old?
Storage matters more than years. Ask how it has been kept.
Will it post?
Ask — bats and bags attract length surcharges. Delivering sports equipment.