Prius Service: Often and Extra Costs

I am taking mine in for the 100K service in November. I am excited to see what they are going to suggest I do and charge me for it. I have worked on cars my whole life for fun so I always like to see what they think they can get away with.

 

I think it's cute that dealerships push FUD on customers, stating they are putting their car through a "severe" driving cycle. This means that - naturally - they mark the service reminder only 3,000 miles ahead, not even the too-frequent 5,000

I had great fun a few years ago when I took my 2000 GMC pickup in for another failed transfer case mode select switch cluster replacement. They gave me a "free" oil change, and marked the sticker 5,000 km and 3 months ahead. I pointed out at the lot, where quite a few trucks had sat 6 months unsold

"So, you've already changed the oil in all those trucks out there? They have been sitting more than 3 months"

That made them STFU. I can't think of a more "severe" driving cycle than starting a motor, driving at a walking pace across a dealership lot, and shutting it off, having run a max of 5 mins

 

Thought maybe this would be a good place to post. Searched and couldnt find anything. My 2005 just hit 100k and I need some work. The dealership told me I needed to replace the drive belt, which I agree with. However they also told me I should change the drive belt tensioner. Already a little suspicious of this dealership since they told me I needed a transmission flush (everything i have seen here says thats a big ol red flag).
Is replacing the drive belt tensioner legit or is this a bunch of malarky?
Thanks for the help

 

Is the drive belt tensioner making noise? If not, it doesn't need to be replaced. (The bearing may be ready to give out @ 100K miles tho'.)