2010 Toyota Prius worth it?

79K miles would be timely for cleaning the Exhaust Gas Recirculation system, including the EGR passages in the intake manifold. It takes me "a day", as a DIY duffer, doing it the second time 'round. Nothing really needs replacement, except perhaps the pliable gaskets on the intake manifold (at interface with throttle body, cylinder head and EGR pipe. See the first two links in my signature (on a phone turn it landscape to see signature).

Not cleaning the EGR system, head gasket will very reliably fail, somewhere around 125K~175K miles.

 

Questions to confirm the answers to:

Have ALL factory recalls been performed? This is recorded in a national online database that a dealer can check, or you can look it up online by VIN number.

Has the oil been changed every 5000 miles, religiously, using 0W-20 full synthetic? If so, the engine is probably in decent shape and does not burn much oil between changes (mine doesn't).

Has all other scheduled maintenance been performed? It's important to the life of a Prius.

Is the high voltage battery fan filter clean? YouTube has videos that show you the procedure to get to it and clean it. Toyota sells a clip-on and a clip-in filter that can catch pet hair and larger particles; either is worth installing after the fan is cleaned. The battery fan filter is like engine oil... Keep it clean and it will prolong battery life considerably.

Has the car been driven often? A Prius does not age well if it sits for extended periods of time. They need to be driven frequently to keep the batteries in good shape (both the 12-Volt and the high voltage battery need exercise).

Has the 12-Volt battery been changed at least three times? They can last 5 to 7 years with care, but if drained often, fail early.

My family and I have owned six hybrids since 2008. My 2010 has 104 K on it and is in good shape. But the high voltage battery is starting to show signs of deterioration (mileage dropped from 45 MPG calculated manually in 2018 to 35 MPG calculated now). The car will probably get a brand new third party battery soon.

My son has a 2009 Gen II Prius with 204,000 miles on it. It runs and drives as smoothly as it did when we bought it used, with 49,000 miles on it, in 2012. It has generally been reliable, with only minor things replaced on it (a few $200 to $350 items replaced).

My wife drives a 2015 Prius V, with 117K miles, and other than the radio, which has always sucked, it's been great.

My other son drives a 2013 Lexus 300h hybrid, which is phenomenal. NO repairs, just tires and regular maintenance in the 35,000 miles he's had it. It's immaculate inside and out, unbelievable for a ten year old car.

Good luck!