It's taken over a year!! I've had to do it in waves - whole house, then again, then again.
The only items I've regretted sending to a charity shop have bee not practical items, so have had to rethink what 'regular use' - sometimes biannually is still regular (thinking decorating items and suchlike).
'Sparks joy'. I was really, really (really!) sceptical about the idea of an item sparking joy. What I've found is that it's not often I get e feeling of pleasure (often it's a 'happy neutral' feeling), but I've been so surprised at the sheer number of items that spark a negative feeling! Often clothes that I don't wear, or memorabilia that has a negative emotion attached (I don't even know why anymore).
I've felt a weight lifting (that I didn't know existed) the more I've decluttered.
My house feels happier - I'm not surrounded by stuff with a negative emotion attached. It's easier to keep tidy - not minimalist, but no clutter and space to put items.
I have more energy, not being surrounded by baggage.
I'm buying less - the realisation of how much stuff is just not necessary has been an eye opener. I'm much more conscious now that I don't have to go through this process again.
I'm not quite finished, but for the first time, I can see that I'm nearly there!
I hope this inspires other people 