In my 8 years here, we have 2 opinions.
1. change regularly, just like any ATF. Personally, I changed every 50 000 miles, just because. But I am well equipped for any mechanical job and sometimes don't really have much to do to sit at home bicker with wife, so some of it is that type of motivation.
2. follow what Toyota says and do not change it at all. We do have owners that did just that - keep driving - and they apparently have no issues with that approach too.
I amn trying to remember, as I do not really keep tally of specific problems... I think we had 1 or 2 members that has PSD replaced. PSD, not HSD, is formal name for your transmission - Power Split Device. Motor Generators in it are cooled by inverter coolant, ATF in it is splash lubricant. This suggests really nothing. It is very basic very simple about 30 min job, likely mostly done for the peace of mind and technical recreation. Again, it is your call. For a well rounded DIY person, I'd say - sure, go ahead, have fun. For someone who has to pay for it - entirely up to you.
Should you go here:
you can see the process. From 2012 upward they moved filler plug to the tire well side, that's about it difference wise.
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I had this discussed beyond reason. Toyota called PSD a CVT for the purpose of Federal registration, to be able to sell Prius in the US.
Does it change gear ratios or not, shows here:
Always in Top Gear
We have discovered above how the Prius transmission uses an epicyclic gear, a generator and control electronics to adjust the spin rate of the engine without the use of either a step transmission or a conventional CVT. We also discovered that a fixed proportion (about 72%) of the ICE torque is sent mechanically to the wheels. Without the ability to change the gear ratio between the ICE and the wheels, we cannot multiply up the ICE torque to get high acceleration at low speed. Although we've solved the problem of letting the ICE spin at a suitable rate when the car is moving slowly, the torque coupling is equivalent to always being in top gear!
We are entering realm of words : as if, like, similar, etc.