I've never physically seen a ghost but something exists, I've had a few experiences and I know that people had died in the houses as they are family houses.
The house we live in is my DH family home which we bought using part of his inheritance, (siblings all wanted it to stay in the family), his Dad died in what is now our family room.
Things obviously moved from where we know they were placed, notably when DD1 was a baby, I put my keys on the side ready to go out. Picked up my daughter and strapped her in her pushchair that was less than two feet away, turned to pick them up and they had gone. Spent 30 mins looking for them, where I'd left them, the usual place I kept them etc etc... Absolutely no sign, went back to where I had put them and they had suddenly reappeared where I'd put them originally.
Anyway DFIL died early 90's in our house and was a smoker.. 10 years later I was standing my our bedroom doors ( all bedrooms doors meet at one point on our landing). Twice I have smelt cigarette smoke right outside the children's doors. We don't smoke. The rooms have been redecorated twice by this point... Carpets replaced..windows replaced, but that cigarette smoke smell was there for a few minutes before disappearing...
My own DF. I rushed to my parents house when my sister phoned me to say that the paramedics had been called for my Dad due to a massive heart attack. I was there in ten minutes and the paramedics were still working on him, he was stabilized enough to be moved, My Mom was faffing about getting clothes for him etc as they were kindly telling her "Get in the car now with Ultrablue" but as they transferred him to the ambulance, one of the paramedics shook her head at me and mouthed "Sorry he's just gone, we will see you at the hospital"
I was downstairs at this point
Suddenly my Dad opened his eyes, took one last look around his hallway, looked at me, smiled, then closed his eyes for the last time.. that was after the paramedics telling me had gone already...