2016 Prius Preventative Maintenance?

Keep an eye on your engine coolant levels. There's a technical service bulletin for 2016-2019 exhaust gas heat exchangers leaking for those model years.

Chassis rust may be an issue where you live; but these cars power-train usually will go 150K with just simple oil changes. Your environment is the worse enemy here. If the car is rusting out; I'd do as little as possible.
On a southern states car I'd recommend all fluids to be replaced, ATF, coolants, brake fluid, spark plugs. Those cars can easily make it to 200K-300K miles, because the bottom isn't going to fall out of them. Sorry...

FWIW: A new Toyota isn't going to fix your mice issues; it's just going to give them something else to snack on.

 

follow the maintenance schedule that came with the car, or find it online.
go by miles or time, whichever comes first.
at 10 years, it's a pretty large maintenance requirement

 

Attached is a spreadsheet summary of the Toyota USA’s maintenance schedule, per the Warranty and Maintenance Booklet, extrapolated to 240l miles or 24 years, a little easier read. Also, a few items, either not mentioned in the schedule, or largely overlooked:

1. Transaxle fluid replacement, at least once, earlier than later. (Not in schedule)

2. Brake inspection, more in-depth than the every 5k mile “visual inspection”, every 3 years or 30k miles. (In the schedule, but often ignored/overlooked)

3. Brake fluid replacement (no mention in US schedule, every 3 years or 48k kms (~30k miles) in Canadian schedule).