
One of the strongest disables in the game. You can use it to setup kills with your team early on, but later into the game it may be better to either initiate with it or hold it off since you're most likely to play as a tanky frontlaner which increases your chances of being interrupted mid-ult

You can use it to both harass opponents early on and setup kills. It can also be used for it's 1sec invulnerability after cast which can save you or your allies (or your enemies) from a projectile or a spell (like X-Mark)
Core
You don't really need it yourself, but it's usually a strong team oriented item. You may consider dropping Solar Crest in favor of Spirit Vessel
Situational Early
Another mana solution, may replace Bracer, but it's more expensive as well
Additional movement speed and armor are pretty much all Bane needs seems he doesn't need attack speed and stats more than he already has
Good for cases when you won your lane early on, but can't finish the game early. Bane struggles with farming after laning stage, so it may be a helpful pickup
Lategame
Reliable disable and mana sustain
Situational
Good thing to have against slows and similar stuff in its nature (X-Mark)
Against strong single target disables (e.g. Doom)
For a hybrid core way when you need armor
Utility
Natural upgrade to Medallion and useful buff for your team
Strong regen aura and useful item to have in general. Good pickup if you're playing more of an utility core and there's no better Greaves carrier on your team
Against high attack damage cores
Against magic heavy lineups
Against silences and purgable slows
Good item to save allies (or yourself) from being focused