Which is the measure to know when its time to release new systems? I believe it is when hardware sales start to stagnate and even with a bigger and growing userbase the software sales start to decline fast. 

2019/2020 - Don't want to buy consoles for 400€ every 3-4 years.

I like this thread.

I dont know man...5 years from now, if every game looks like The Witcher 3 im fine. But the same could be said about last gen graphics when Last of Us came out. People would have been fine with those graphics for a couple of years more.

At the end of the day, im glad that the 5 years gens ended and now we have console that last much more. Playstation is known to be very supportive with its systems, and you know that if you buy a Playstation console, you will have 8 to 10 years of games.

But i understand the situation of (for example) Nintendo with the Wii U, the system is just not doing well comercially and they have to do something about it. They know that the games wont make the console suscesful, so they have to release a new one ASAP.

Its not easy to answer your question OP, but im eager to see VG Charterz opinions.

Pretty much this. I can't understand why there are people who would rather have shorter console generations, gaming is expensive in many countries, so expanding the lifetime of the consoles allows people to spend money on more games instead of saving up that money for the next console.

THIS.

Every 6 years to me is ideal. Enough time to get nice library of titles and see decent leap in technology.

There is no right time. It typically depends on what the current gen has yet to offer, and what the next gen promises. For me, this usually relates to power. Each generation needs to have sufficient power to allow devs to make truly next gen games without the limitations posed in earlier gens.

The wii has been to me, a half generation behind, and the wii u is to me, a full generation behind. Sales mean nothing here, I am going purely off of technical capabilities. They may have gimmicks tied to them, but I view the gimmicks as forced peripherals, not generational leaps

I do think ps3 and xbox 360 tried to start the 7th gen earlier than it was ready for but the 8th gen has launched at a pretty good time to be financially reasonable while showing excellent improvement.

I also agree with this, i like to measure generations by the power of the consoles and not the time of their release.

For the most part, every console of each gen has been relative equivalent when it comes to horse power. Nintendo being the exception since the 7th gen with the Wii, and now with the Wii U.

I reeeally hope they make a good use of their money and invest in a proper R&D so the NX can be at the very least, equivalent to the Ps4.

Im sick of "intra" generations.

You are mostly right. When hardware and software sales start to decline is when everybody starts to talk about new machines.

Another hint of that is when game studios that start to complain about features they would have liked to put in the game but couldn't because of the hardware limitations, which is also an indication that something is going on behind the scenes.

How about right now? I mean before they start with VR and embarrass themselves with their puny APUs.