Breitling 36 mm automatic is the subject of this note. Lay the watch on a plain cloth under a lamp. Read the case flank before you read the dial, because the flank shows tool marks and a polished edge that a photo crops away. Count the lugs. Note whether they are drilled. A drilled lug means the strap can be changed with a spring bar, and the hole should be round rather than oval from a bar that was forced. Flex the bracelet at the first link. Stretch that does not return is wear, not a style. The clasp should close with one click and sit flat. If it stands proud, the fold has been bent. Look through the crystal at an angle. Dust on the inside of the glass is a different problem from a scratch on the outside. Write which one you see. Then set the hands and watch them for a full minute so you can say whether the seconds hand ticks or sweeps. That single observation tells you the kind of movement in the case. Record it next to the reference engraving. The two notes belong together.
How it differs
The size written down for this record is 36 mm. Measure across the bezel and from lug to lug before you accept that number. The seconds hand should sweep. That is the check for an automatic watch. Wind the crown and listen for the rotor only if the case back lets you. People change the crystal, the clasp, and the strap more often than they change the case. Write which part looks newer.
What to check on a used piece
Read whatever engraving is on the case. Measure the width. Watch the seconds hand for a minute. Look at the end links or the strap holes. There is no price in this note, and the note does not grade the watch.
Common mods
Common changes are a new strap, a shortened bracelet, a replaced crystal, and a polished lug. Describe those changes next to the size and the movement type. The case you measured is the watch you have, even when a listing used a different width.
What people change
On the Breitling 36 mm automatic, people change the bracelet, the case, or the movement.