Hey guys,
 
I am wondering when I'll have to upgrade my gaming rig - currently playing games on max settings on a 1440px1080p 165 hz monitor. Furthermore, I am using some forms of AA (but not always maxed AA since 1440p has limited jaggies as it is) and might upgrade this to a 4k monitor in a year or so.
 
1080 SLI
i7-6800k OC @ 4.0 Ghz
EVGA X99 Micro 2
64 GB Ram
EVGA Supernova 1000W 80+ PLAT
 
I'm most worried about the CPU since it seems like a pain to upgrade by myself (GPUs seem easier to upgrade). PSU also seems concering because I'm running an SLI system and thus more powerful future GPUs will need more power. 
 
Any thoughts on when I should upgrade these components to fully appreciate 4k (assuming my current rig doesn't fully take advantage of the 4k resolution)?
 
 
Thanks so much!
 
-Potentialism

I am sure the best answer is when you are no longer satisfied with the quality and you have some cash :)
I was running 2 580gtx's until last Monday and was completely satisfied. I had them since 2011. However I am playing 2 games that my 580's couldn't handle so I upgraded. Luckily I only needed a graphics upgrade because my i7 2600k is still a beast :)
 
 
 

hah, still running games on an X58 system using 32nm 6 core chips.  fun stuff! :)
 
With that system you'll be set till we hit moores law

In a way, per this guru3d review of Broadwell-E, you made a good choice on CPU since it is the cheapest of the Broadwell-E platform and getting the higher core models for 1440p would be a waste of money since more cores doesn't do much when gaming max detail (games become GPU limited).  

But in this guru3d review of GTX1080 SLI, in which you actually have both cards, the implication is that 1440p isn't high enough a resolution to utilize the graphics cards, that their scaling shines at 2160p (popularized 4K).  Oddly enough, they tried to conclude that at 1440p, the SLI'd GTX1080 was suffering a CPU bottleneck which kept the pair of cards from scaling properly.  But comparing the results in both reviews proves that the scaling of the cards were dependent on the resolution.  If the CPU was truly bottlenecking, then the change in resolution shouldn't have done anything, as if everything in the system is held back by slow processors.  High-end graphics cards need high resolutions to shine, that's just how it is.  Unless you play CPU-limited games, changing the CPU won't do much.  Your future potential upgrades are dependent on what you do, that's why there isn't a one-size-fits-all consistent simple answer.

Someday soon, say next year at this time, there will be single graphics card (GTX1180) that will be as fast as your GTX1080 SLI.  You could put two of them in your system, but don't scapegoat your CPU for why they don't scale, the problem is your resolution, you need to get into 4K for that.

3 to 5 Year at best 4 to 6 years for your parents 6 to 10 years. 

For gaming your CPU should be fine for quite a long time. I just recently upgraded after 4 years and not because I needed to but I just felt like it.

Do you guys re-purpose your old machines?  I'm sorta in the middle of it.

MNFirstBlood
I am sure the best answer is when you are no longer satisfied with the quality and you have some cash :)
I was running 2 580gtx's until last Monday and was completely satisfied. I had them since 2011. However I am playing 2 games that my 580's couldn't handle so I upgraded. Luckily I only needed a graphics upgrade because my i7 2600k is still a beast :)
 
 
 

+1.... I think Mr. Blood,  :) , really gave you the best answer. Adding to that, your asking a difficult question really cause everyone does different things and have varying amounts of computer knowledge with PC's. Being this is a enthusiast forum, your going to get answers on here that are probably much longer than your normal user because most of us are bent on getting every drop of power outta every component we have. Im still running the rig in my signature and it does very well in every game I play, but I NEVER jump on any games when they first come out because they are just riddled with issues and are unfinished works. Unfortunately, this isn't a problem that has cropped up lately.... its been going on for quite awhile now. So by the time I get a game its well optimized and it has all its necessary updates, which means with some games I can run them on my intel 775 rigs from years ago with up to a 7xx series gpu and be pretty well off with a little bit of finesse. The rig you have now I think youll be able to really squeeze a great gaming run out of for another 5 years easy, if you want to. Its not so much the hardware that's lacking, its the horrendous coding and rushing of games to market that's made them hard on hardware with memory leaks and not being able to utilize more than 4 cores, broken sli, graphics drivers corrupting windows installs or making monitors flicker and artifact, etc.... imo.