Why do cricket teams declare?

[HangTime]

...instead of just launching a massive slog?
One thing I've never been able to get my head round is the benefit to the team from a declaration compared to just telling every batsman to attempt to hit every ball for six. If they get out, they haven't used up much time and the wickets lost are irrelevant if you are going to declare your innings anyway. But the point is you can accumulate runs quicker and potentially build a bigger more unassailable target.

The only thing I can think of is protecting personal averages but that seems to go against the team ethos. Surely the important thing is trying to win the game, not whether Joe Bloggs got 50 not out or was caught for 62 and hence reduced his average slightly.

Here's an example, it's after tea on the 4th day. Your team has a lead of 320. You can try to accumulate another few runs and then declare to get a bowl at them before stumps. But why don't you just go ballistic, tonking the ball here there and every where. Maybe you get bowled out for 335. Who cares, you were going to declare anyway.

 

[HangTime]

Those extra runs are useless if you don’t have enough time to bowl your opponents out.

it’s a balancing act between ensuring you have enough runs to avoid defeat and enough time to bowl the other team out. It’s really that simple.

I know, I'm not advocating batting for significantly longer. I'm advocating playing MUCH more aggressively so you are either scoring at an extreme rate or getting out. It's exactly because it is a balancing act that I'm bringing this up, because the point is if you score runs quicker then you have a bigger lead with X amount of time left, or you reach the point where you can get more time bowling at them because you got runs quicker, unless you started slogging way too early.

They more often than not do throw caution to the wind in the run up to a declaration. Sometimes they might be trying to give someone enough time to hit a ton.

Also, if they’re into the tail, they don’t want the batsman exerting themselves too much as they’ll be needed to bowl straight after.

They play more aggressively ahead of a declaration but not the extent I'm talking about. They might score 6 an over. I'm talking about plundering 30+ off 3 overs and losing a few wickets. I do appreciate with an old pitch and test match fields it's not that straightforward to score big but the point is they don't need a huge amount more runs and nor should they care about losing wickets.

The final point is a good one I hadn't considered, wanting to keep the bowlers fresh.