The hardware is older, but if you aren't having struggles with what you on a regular basis, I wouldn't worry about upgrading.
If you wan't to spend some money now, vid cards are a good investment as they aren't tied to any specific type of system, so you can transfer them to a new build down the road.
1070/ti isn't bad, you could also look into the new 2070. It will be a bit more pricey but part of that is newer technology that isn't yet implemented. It would be more of a future proofing thing, but the RTX 2070 performs about on par with a 1080 for reference.