You
generally want to have 3 points at Reactive Armor at level 5 in order to sustain
your HP on any lane. Now the dilemma is between the other two abilities.
If you’re
playing offlane, then you need to consider if the enemies can kill you – if the
answer is yes, put a point in Timber Chain to escape. If they’re weak laners
and you feel they can’t deal with you, it’s not mandatory and you can get
Whirling Death to harass them better.
On the safe
lane, it depends on your enemy – if it’s
a melee hero, get 2 points in Whirling Death before level 6. Against ranged enemies, you can either choose 2 points in
Timber Chain or 1 in both.
On the mid lane, people generally put 2 points in Whirling
Death as there are no trees for Chain.
If you’re
still laning at level 7, you can put the final point in Reactive Armor. You can
also delay it in order to get a point in Chain (if your build was 2-0-3 before
that) or Whirling Death (if it was 0-2-3).
After level
7, Whirling Death is good for farming (more damage, lower mana cost) and fighting melee heroes. Timber
Chain is better for chasing. You can also distribute points evenly between all
skills – it all depends on what you want in the specific situation.