What's wrong with your system? If it runs fine you are good for a few more years. I have a computer I built in 2011 with an eight core processor, an 990xe and a Rampage III Black Edition motherboard. I added a couple 1070s in SLI and wow. To be quite honest, it still does the job and I built a couple new systems this and last year, when the old system still does the job. Do I have any regrets? Yup, I do. I could have sat on the money for a couple more years and kept on using the older system which still runs well and is as good as most current builds.
The bottom line: In a couple years, the performance/cost ratio is just going to get better. It always does. Hence, more money in the pot for down the road will mean building an even better and more future proof system then.
The question: Is your current system up to snuff? Does it do the job as well as most current builds?
Just my two cents.