Cribs produced since 2012 have been forced to meet the Consumer Product Safety Commission's strict safety regulations. with that said, you should be making a checklist of all the things that are discussed below
This is even more essential to align through the safety checklist if you are thinking about a used crib that may not meet current requirements, especially if the crib is more than 12years old. so it would be best if you look for the following things before buying a used crib mattress
Make Sure the Crib is the Right Size:
The crib rails or wooden beams should be no wider than 3 inches (about the width of a Pepsi can) and the bars should not be cracked or missing from either side. The top should be at least 28 inches from the top of the mattress on the crib rail. Finally, the top of the headboard can line up flush with the corner posts or be much taller than 18 inches. If your kid tries to climb out, posts in between these heights could capture your little one.
The Sides are well polished
Corner poles should be aligned with the end panels (and they shouldn't be more than 0.0625 inches gap between if there are small corner posts). You'll need to sew them off and sand down the hard spots, outside and far from your baby's place, and if your corners are smooth, your mattress won't get damaged due to the rough edges of the edges
The Hardware is Secured
The hardware, locks, screws, etc., should be tightly secured in a sturdy crib, with no sharp edges or rough areas and no spots that can pinch or otherwise damage your beautiful kid and damage your mattress from the inside. The timber of the crib should be free of defects or breaks. (And with tight joints, the whole crib should be very durable, including the arms, slats, and all.) Never replace anything at all from the hardware store for a crib's original components. Instead, the components have to be bought directly from the manufacturer of the crib
The Mattress should be perfectly Fit Inside
Make absolutely sure that the mattress fits nicely with the crib inside. Try the two-finger testing to evaluate crib safety: if you can squeeze more than 2 fingers that are small between the mattress and the crib, the mattress is not a perfect match. The Bed will be perfect for your baby's comfort if you feel that the Bed is hard to make. Also, take the plastic off and throw it in the trash immediately if the mattress is new. Make sure the mattress is indeed solid, too, because soft mattresses increase the risk of Sudden infant death syndrome. Test it yourself instead of going through the firmness level on the mattress label: If you press down hard, the mattress, it should remain steadfast and bounce right up.