I've played the game for almost 50 hours at this point, and I have yet to see my bases get attacked in any way. I've that you'll get notifications for it, and it can happen whether you're at your settlements or not. Any ideas what's going on? I have a few of my bases built up pretty well, but they have never been attacked.

I did notice that the two settlements of mine that got attacked didn't have any defenses

Lower chances of attack if your defenses are higher than your population and other resources.

You get attacked somewhat once a week if your settlement produces 500+ Resources in water/food with only 20 or so defense

Once a week? Do you mean in-game weeks? Also, I don't think any of my bases have up to 20 defense, they're all around 9 or so. Is my defense not high enough to be attacked?

If your defence is way higher than your pop/food/water, you'll get attacked less often.

When it does happen, it's random - you'll get a notification, but it's easy to miss, so keep an eye out. Also, you have to go back in the event of an attack - otherwise your settlement will get broken, regardless of other defences.

Also, you should get an early attack on Sanctuary as soon as you've got something worth taking - after you fend them off, talk to a Settler to complete a dialogue about you being there to help. That 'kicks off' regular raids.

I'm having the same issue.

My defense rating is quite high, as I have 5 heavy turrets, 3 shotgun turrets, and 3 guard posts.

I sometimes get random XP while out in the wastes, so that may be the source and I just never see the notification.

My defence value at the Starlight Drive-In is 100 and they get attacked quite often. Sanctuary Hills on the other hand hasn't been attacked at all yet.

It's easy - plant loads of food... Have no defences and no walls and watch that settlement become the target of the day... You will get raided

I've only got Sanctuary Hills, Gray Garden and Oberland Station so far. Out of the 3 only Oberland has been attacked. It happened while I was in that area doing a quest so I'm thinking maybe you have to actually hang around the area for a while for attacks to happen? When I go to Sanctuary I always fast travel there, plus it has an extremely high defense rating, and Gray Garden has 0 defense but I literally never go near it.

You might be on to something there. My Starlight has no walls, 7 settlers and heaps of food growing. It has about 8 Heavy Laser turrets though.

Abernathy Farm gets attacked all the time for me. Sadly the last time I showed up to save them I saw the body of Mrs. Abernathy lying amongst her plants.

Look on the bright side you get a clear run at her daughter now her mum's out of the way

if you want to get your settlement attacked, focused on toggleable defenses.. IE turrets that require power to operate..

dont quote me on this since my memory is not the best but if i remember right those turrets will not count to defense number when turned off so you can effectively "hide" your defense to encourage attacks, then just turn them on and watch the fireworks.

I was in the same boat until yesterday. 90 hours and not a single attack. I spotted a gap in my perimeter at Sanctuary and promptly plugged it with an MG turret.

Was on my way back there and I heard the siren. Started sprinting and followed the sound of gunfire. I found a single, solitary Super Mutant armed with a board, trying to attack from the bridge to the North that leads to Vault 111. I know they are stupid but there are 5 turrets that could get a shot at him and he had a board.

A little later on, Greentop got attacked. 2 raiders with pipe guns vs heavy MG and laser turrets.

Weird...what difficulty are you playing at?

On my first playthrough I built 2 guard posts at a gate, 4 MG turrets and 2 shotgun turrets.

After about ~25 hours in the game a massive attack of Super Mutants started. About 3 dogs, 4 muties with armor and boards and 2 muties with rocket launchers...Preston was stationed at the guard posts, so no problems there...