Do all modern toilet tanks have overflow tubes?
I ask because I went on vacation just a couple of days after my
toilet started to drip in the tank.
I'll be gone for a while so drips can quickly get out of hand before
you know it.

If it has an overflow tube I should be OK until I get get to it.
BTW, this toilet is 12 years old now.
How do you stop a drip on the handle part?
Will I need to call a plumber?

It's a very slow, irregular drip, maybe once every 5 seconds or more.
TIA