A rune page for Renekton reasoned from its class, range and damage type — with the thinking shown rather than a win-rate table.
Rune pages get copied far more often than they get understood, which is why they stop working the moment the matchup changes. Renekton is a fighter whose job is to trade repeatedly, survive the return damage, and win the third exchange rather than the first.
At 125 attack range Renekton has to walk into damage to deal it, so every trade begins with a decision about whether you can afford the walk.

Precision — Fighters win the third exchange, not the first. A keystone that stacks through a drawn-out trade is the one that matches how the class actually wins.
Gain stacks of adaptive force when attacking enemy champions. After reaching 12 stacks, heal for a portion of damage you deal to champions.
Killing a target heals you.
Takedowns on enemies grant permanent Attack Speed.
Deal more damage to low health enemy champions.
A starting point reasoned from class and range, not a win-rate ranking. Matchups change it.
Take Dominus at levels 6, 11 and 16 — the ultimate is always worth the point it costs.
For the basic abilities, Ruthless Predator (W) gains the most from being ranked: its cooldown falls by 8 seconds between rank 1 and max, which is the largest improvement in the kit. That is the usual argument for maxing it first.
This is reasoning from the cooldown data, not a win-rate ranking — a matchup that punishes you can invert it.
The page above assumes an even matchup. Against a lane that beats you up early, survivability runes buy you the levels you need; against one you outrange, damage runes compound the advantage.
Renekton uses Fury rather than mana, so "back when you are out of mana" does not apply — track the bar itself.
These are the designers' words, not ours — the tips shipped in the client for Renekton.