How to properly itemize on ADCs nowadays?

Hey guys I wasn‘t into league for quite some time and I just came back after 13.10 and was kinda overwhelmed by all the item changes. After some games I felt like I couldn‘t really decide on what items to buy in a rational order to be as effective as possible in every stage of the game.

To specify my struggle here are some questions that come to my mind regarding the new items:

• when do I buy Kraken Slayer now? Is it still considered a tank-shredding item or can I buy it against squishier comps as well to amplify my damage (if I play an adc who loves to buy a lot of attack speed —> Kog, Vayne, Cait, Jinx etc.)?

• Is Botrk a viable item to buy even on non on-hit champs just for the sake of better kiteability and/or to melt hp stackers on crit champs like cait for example?

• I see a lot of people buy BT as second or third item now. Is the additional AD so impactful that it‘s kinda essential?

• what are the optimal tank-shredding items? Does LDR alone still seal the deal or do you rather buy LDR + Kraken + Botrk? If yes, in which order?

• When do you want to get Statikk‘s Shiv? I really liked the item back then and I‘d love to buy it early on but on 3rd party sites like lolalytics, u.gg, metarsc etc. you don‘t really see people buying it except on some funky veigar builds.

• is it just me or does it feel hella awkward to play AS-depending Champions early game because all the items lost their AS and swapped it for AD now?

• How about Black Cleaver as a tank-shredding tool on adc?