activation effects

If a characters effect (Sideline or Not) does not say "you may" does that mean you are required to activate it every turn.

Example: 

Yusuke the Raver 
Effect: Main: Abuse:  "Discard a card at random from your hand to search your deck for a card and put it into your hand at the end of the turn. Discard a face-up Technique in Play"

Kuwabara, Noble Champion
Sideline Effect: Main: "Discard the Top Card of your Deck. If the discarded card is a technique, discard a face-up attached card in play."

So my questions

1. Am I required to activate these effects every turn even if i don't want to because it doesn't say you may (it also doesn't say you must)
2. If a am required to use them and im the only one with a technique in play, I assume I would be required to discard my own technique.

Thanks.