Parents with dementia - what was the timescale and progress?

For my mum, who was in her early 60's when it was first noticeable that there was an issue, it was 14 years. At diagnosis she had a lot of word finding problems, didn't know my name, only knew her own first name, and had problems with eating and drinking. She'd then have sharp downturns in her ability at intervals and by the time she died she didn't recognise anyone and didn't speak really. She died 5 years ago - just shut down and stopped eating/drinking, she had covid, but actually it was a very gentle death for her in the end

It seemed like a long time for FIL - MIL complained about him asked for help - he did the tests etc but they didn't want a diagnosis. That was about 4 years in total. Then there as a potential scamming and report by social services that MIL was acting strangely when they visited FIL. We finally got a diagnosis for FIL as mixed dementia. We then moved them to assisted living near us about a year and 6 months ago.

MIL couldn't cope she was referred to the memory clinic and her behaviour became more erratic. She went into respite from FIL for 2 weeks and never came home. She became aggressive and tried to kill her carer by pushing them into the road. They got an emergency DOLS on her, got a diagnosis of vascular dementia - pushed through her diagnosis as she'd already had the scans we were waiting for the results and we said she's not going back to FIL. She went straight into a dementia care home which she's been in for about a year now. We were all focusing on FIL that we didn't notice she was worse than him. She masked it so well at home but when moved it all fell apart. FIL is coping and living semi-independently in assisted living, and visits MIL every day. She is aggressive and confrontational on occasion in the nursing home. But they changed her meds and seems to sleep quite a lot now.

My mum was diagnosed late 2020. Still living at home but gets very confused by everyday stuff like adjusting heating and money but still shops and cooks for herself. Basically she's fine with stuff that's very routine and doesn't change but the slightest change, like a change in design of a bank card, totally floors her.

my mum went from being diagnosed with dementia in 2021 and died two years to the day of dementia and went to the very last stages of it so couldn't eat couldn't walk couldn't talk doubly incontinent at this stage I was relieved she didn't go on and on as she had no quality of life she was just short of her 81st birthday.
Every case is different though

Sorry you’re going through this. My dad was diagnosed 10 years before he died, but his memory didn’t change at all in that time. People who knew him were amazed to learn he had dementia as he showed very few signs (if any). He died at 85