How to Increase Affection With Companions?

[7ChaosTheory]

My current affections level so far:
Kana = 2
Yui = 4
Kasumi = 2

Can I only level them up through random occurrence during daily tasks or do they increase as I progress in the game? I'm currently on the 100th day and defeated the dark matter.

[mrross]

Defeating dark matter is not the end. It's around day 200 in my game, something is happening still from time to time. And Kana's affection isn't maxed yet. Yui and Kasumi are at max, but I don't think it affects gameplay in any way.

[NEil]

They only level up through random daytime event.
You need leftover energy for random events to occur.
max levels are:
Kana 5
Yui 6
Kasumi 5
They give battle skill through affection level.
They are truly random, I still didn't max everything at 200 days.

[7ChaosTheory]

Okay. Thank you.