When my mum had a crisis and we realized it was dementia I desperately wanted to know where she was at and how it would progress. (hindsight is a wonderful thing - she probably had dementia for 3 to 5 years before hand - I phoned her GP 5 years before hand with concerns as she'd forgotten some things completely out of character - I didn't see her very often and think she was in hostess mode when I did).
I think it was the seven stages I looked at and was shocked that mum was only early stages as so much of her had 'gone'. But some bits were better than the list said and some things worse. Mum moved into sheltered extra care, and started taking donepezil and everything stabilized - in particular her anxiety, which has never reappeared. I think the anxiety went with the removal of the difficulties of working out how to cope with day to day living in her own home. Being in a small flat with a carer popping in to give her meds twice a day, and only having to worry about the next jigsaw piece had an immediate effect (after a short settling period) and the donepezil prescribed a couple of months later also reduced anxiety.
I realised from reading the forum that it doesn't really matter what stage it is, everyone is different and I haven't looked at the stages in the last 6 years.
I guessed mum would be in her flat for about 2 or 3 years and a care home for another 2. Seven years later mum is still in her flat, but probably needs to move to a care home. Each issue has been tackled as it has arisen with more care visits added by the wonderful in house care team. She could well live another 5 years although I hope it is less as she sleeps most of the day and doesn't do anything beyond eating and staring at TV if the carers remember to put it on, she's too deaf to hear it.
Mum is still continent and mobile although I assume this will go in time, her mobility is affected more by the dementia than her arthritis.