Sterling silver or 14K gold fill everyday hoops.
There is no one size that it perfect for everyone.
To determine your size, measure the distance from your piercing to the outer edge of your ear in millimeters then choose your size accordingly.
For any other ear piercings, I suggest the same method but size up one or two sizes.
>>The first photo shows a 5mm hoop, the second photo shows a 6mm hoop.
>> The third photo shows the proper way to open the hoop.