the Valheim Wiki states that army raids can be disabled by killing next biome boss.
so for trolls etc its killing The Elder.
the random raids however wont be disabled; so if youve killed The Elder you should have disabled "the forest is moving" base raid
you can however still get "the ground is shaking" which will be trolls attacking but is a random event that is triggered by you being close to your base (or a base; which is campfire, bed and workbench)

At one of my bases the mobs were pretty numerous during The Forest Is Restless and they happened every few days. However, after I expanded the base size the event comes seldom and the mobs are down to a handful. On the other hand some bases did not see a change as they were expanded. Valheim logic - remember Odin pretty much does what he wants.

Originally posted by BoneSage:

Iirc base attacks also won't occur if there is no acceptable spawn area within a certain radius.

I have an island base with Workbenches and Wards over the entire island and I haven't been attacked since I finished it

I only have benches to make a small wall, I haven't covered that large of an area.

Originally posted by FTZ35:

Every 46 minutes there is a 20% chance of an event occuring. Most events can only occur if you are in your base, but there are some that can happen anywhere. There are some that can happen anywhere but those only start later.

I realized that I just don't spend time in my base ever so the attacks never have a chance to spawn. I am always porting to my swamp base and sailing back with Iron nonstop.

Iirc base attacks also won't occur if there is no acceptable spawn area within a certain radius.

I have an island base with Workbenches and Wards over the entire island and I haven't been attacked since I finished it

Every 46 minutes there is a 20% chance of an event occuring. Most events can only occur if you are in your base, but there are some that can happen anywhere. There are some that can happen anywhere but those only start later.

Iirc base attacks also won't occur if there is no acceptable spawn area within a certain radius.

I have an island base with Workbenches and Wards over the entire island and I haven't been attacked since I finished it

Originally posted by Farmer Rat Joe:

I've had my little town attacked three times now and on the second I erected a wall by first raising the earth and throwing a wood wall up for looks now I haven't been attacked in like 30 days.

Do they just stop or will I get one again? Will they pick up again if I move my home base to somewhere like the plains?

You need to be inside your base longer. If you're just spending most of your time somewhere else - you won't get any attacks.

Special base attack events, like "Eikthyr rallies the creatures of the forest," should trigger at randomized intervals whenever a player character is within a certain range of certain base structures. I haven't calculated a mean time to happen, but if it's been a long time, that's just luck, or perhaps you've been out exploring more than normal.

Relocating your home base won't affect this at all - wherever it is, when you're there, the base attack event may trigger, and if it does, you'll get hit by whatever the current event is (based on whatever boss is next for you to fight).

You wont get attacks if you are out and about the place, the trigger seems to be if you hang around too long by a workbench at minimal, your base will trigger the attack if you stay at home too long (very annoying if you are trying to make a big build).