GTX 1070 Minimum OC Suggestion(ASUS Dual 1070)

Hello guys, I am new to this mining RIGs and I got few 1070’s running at 440-455sol/s on EWBF 0.3.4.
I don’t want to overclock and decrease its lifespan.
Stock Hashrate: 440sol/s (100% power, Core and Memory clock 0)
My Settings: 445-455sol/s (85% power, 90+ Core and 450+ Memory)

My question is since Stock hashrate not much difference, mining with stock can increase its lifespan and stability?
Or any minimum/smallest Overclock settings?
Does my current settings considered as HIGH or LOW overclocking?

You are going to get a lot of different opinion on this:

You will probably get max life @ stock, but your power bill will be lower if you reduce power consumption but now you’re starving it ever so slightly from what its creator’s think it should have to run optimally. Then add you have increased the core and memory and making it perform at stock or higher than stock levels using less power.

in the end, the cards are running 24 / 7, they were never designed to run 24/7/365.

Keep them cool, clean, and use the warranty if one fails.

Since I got 2450W PSU+electricity in my country is cheap. So I am guessing stock 100% power settings good for me.
So this miners overclocking at 70% 80% power is all about using less electricity. No other reason right?

thats it, less power consumption lower power bill

My Rig: 980ti with watercool.
OC: +170Mhz CoreClock

Using dstm: 500~510 sol/s.
Using EWBF: 470~480 sols.