Holy shit is that why it's a thing? Cause you would be checking the age and it's rude?

Was it a trojan horse?

We can now verify that Squidward is in fact a 30 year old horse

From Wikipedia:

The Galvayne's groove occurs on the upper corner incisor, producing a vertical line, and is helpful in approximating the age of older horses. It generally first appears at age 10, reaches halfway down the tooth by age 15, and is completely down the tooth at age 20. It then begins to disappear, usually half-way gone by age 25, and completely gone by age 30. The groove is named after horse expert Sydney Frederick Galvayne who claimed he had invented the use the groove to age a horse; however, it had been earlier described by his teacher Professor Hamilton Sample.

what, you don't got tooth line? hey everyone, laugh at abbadon. they don't got tooth line

Smashing!

27 I'd say

Amazing!

Also "don't look a gift horse in the mouth"

Well, sort of. While it does refer to horses, it’s actually a reference to how their gums recede as they get older, making the teeth look longer (at least according to Brewer’s).

You just typed it. It looks like a three and five next to each other, in that order.

What'a ya? Dense, or somethin'?

That brown stripe just keeps circling around like it's loading new teeth.

They get triple stripes on account of the prestige system.

Kind of like the 30-year-old teeth, but with no skin and gums...