To be annoyed when FIL lets himself into our house with his key?

Well a nanny wouldn’t knock when bringing the kids home. That’s different than not knocking usually.

OP seems to be enjoying making a massive deal out of this. A key in the door, a chain or a bolt are all easy solutions

Is there any reason why you can’t put a chain on the door or an inside bolt?

OP I have had the exact same thing with my lovely in laws. MIL was helping decorate our house (bless her) while I was pregnant. I'd been uncomfortable about the walking in with the key but didn't feel like I could say anything to DH. He then found her pottering about downstairs while we'd both had a lie in - I had a day off and didn't know they'd arranged for her to come over that day. Finally spoke to DH about it, apparently him asking me when we moved in if I minded them "having a key" meant to him that I was fine with them using it every time they came round.

I suggested not to hurt feelings especially with all the help we were given that DH just met them at the door every time they came over. I would like to put a bolt or chain on for added security which we've not got round to, but so far it's worked just to gently reset the expectation.

Smart lock, give him the code on the days he's picking up the kids, change it after he drops them off.

Haha - I cross-posted with you 😂😂

Tactical nudity is the solution I reckon 😂

I would arrange to be stark bollock naked - (en route to have a shower as you’ve been doing DIY/gardening etc)) - when he lets himself in one day - you can feign shock with “oh, wasn’t expecting anyone to walk through the door!!”

Would that shock him into ringing the doorbell next time? 😂

Failing that, I’d bolt the door every single time. Can you invest in blinds so he can’t peer through the window at you?

It’s just a process of training him 😂. I understand it’s an awkward conversation to have, especially as he helps you so much, so making him knock each time is a subtler way of asking him to respect your privacy.

Gosh no what if you were naked or in the middle of an intimate or private matter? That’s really presumptuous of him and he needs to be politely told not to burst in unannounced

My df does this too. It used to drive exdh up the wall. We'd come home and he'd have done odd jobs that we didn't want doing. Hang pictures on walls, that we didn't want hanging etc. We had to confiscate the key in the end. when we divorced df copied himself a new key when he was with dc, and it started again. It doesn't seem to matter how many times we tell him not to just let himself in he still frustratingly does it.

You are making a massive deal of this. Put up or shut up

. If the door is bolted, he’s up impatiently looking through the window.

Surely he'll then ring the doorbell though?

I would keep doing this.

I also think you could possibly stop him getting in by putting key in your side & then pretend you haven’t heard him knock 🙃

I think WFH is exacerbating the problem. My FIL used to have a key & they looked after children & helped with walking the dog. So we found it more of a help than a hindrance. Could you try to say he can’t pop in during working hours? I think you do risk upsetting him & potentially him not wanting to help out if you come down too hard on him. Are you prepared to lose what help you have? Not only does it save you money but it’s nicer for children to go to grandparents than after school club.

Instead of just dropping hints just get your other half to say "I know you have your own key Dad, but I'd appreciate it if you rang unless you know we are away / out because we find it really intrusive. We really appreciate your help but it means we feel we don't have the full privacy of our own home. We'd be really grateful if you could respect that"

Be grown ups and actually talk to him about it rather than fanny about around the subject.

You need to bolt the door, I think. If he has to wait a few minutes every time he will get the hint.or he will raise it and you can tell him why.

So, now’s your chance to make a decision. Which option are you going to choose?

I don't think it is unreasonable to have a key and yet respect it isn't your house.

I have a key for one neighbour's house, one for dd's house, and one for ds's house. I wouldn't dream of letting myself in though, unless they weren't there and had asked me to go round for some reason, or if there were some emergency.

My Mum has had a key for all my houses. For emergencies. The only time she ever let herself in is if I've asked if she could help me by waiting in for someone when I was at work or away.

As we are all different, then I expect there are people who would appreciate someone they trusted letting themself in if they were on a work call, rather than having to leave the call and let them in.

The reason I think YABU OP is that you have only "hinted".
If it annoys you, then why not say "Bob, can you not let yourself in please - the key is for emergencies / if we aren't there. It really worries me when I hear a noise downstairs when I think I am alone in the house.
Obviously, this would be a lot easier / more effective if you'd done it from the start.

Just leave your key in the door on the other side so he can't get his key in! Then he'll have to knock 🤷‍♀️

We had a builder like this, gave him a key to work on our house while we were away as they had to turn the water off for a few days but he then proceeded to let himself in at every opportunity. He even gave the key to other tradesmen unbeknownst to me and they started letting themselves in until I bolted in from the inside and they nearly broke the door down cos they couldn’t work out why it wasn’t opening. I was home and they could have knocked as I told them.

DH said they weren’t harming anyone having the key(!) Didn’t matter to him as he was at work, I was often getting changed from dog walking clothes to work clothes when the builders would turn up.

Came to a head one day when I caught the original builder rifling through DH’s expensive tools and trying to take them. He was so shocked I came home and said ‘ oh I thought you worked all day today and wouldn’t be here’
I can see that you thieving twat.
I asked for the key back at that moment and I told DH he’s not welcome in our house anymore.

It’s a real intrusion of privacy and I understand why you’re upset about it.

True, that’s the easiest option