1"This and that" / "one thing or another" — refers to various things or matters, often used for doing several different things one after another.
引っ越しの準備であれこれ忙しい。
I'm busy with all sorts of things preparing for the move.
店にはあれこれと面白い雑貨が並んでいる。
The shop has all sorts of interesting knickknacks on display.
彼はあれこれと意見を言ったが、結局何も決まらなかった。
He gave one opinion after another, but in the end nothing was decided.
あれこれ悩んだ末に、留学することに決めた。
After agonizing over various things, I decided to study abroad.
2Read as "kare-kore" (not "are-kore"): means "around" or "roughly", used for approximate amounts of time or quantity, as in かれこれ十年になる ("it's been about ten years").
彼と知り合ってから、かれこれ十年になる。
It's been around ten years since I got to know him.
費用はかれこれ五万円くらいかかるだろう。
The cost will probably be around fifty thousand yen.
待ち合わせの時間から、かれこれ一時間が過ぎた。
About an hour has passed since our meeting time.