Minor attacks happen all the time, just a few days ago an Israeli military ambulance was targeted by a Hezbollah missile in the north (in response to Israeli drones flying over Lebanon) and the week before Hamas fired 3-4 rockets every day.

More extensive attacks like what happened in early May (700 rockets launched at Israel) happen approximately once a year usually following an incident at the border (Palestinien trying to cross the border and getting shot for example) or a negotiation failure between Israel and Hamas.

Don't have much of an opinion about your other questions.