This is a really good point.
I always planned to retire as early as possible, but when the reality of the situation hit home - i started to realise that a slow descent into retirement would be a better route.
So working a 4 day week for a while, then 3, then look to give it up. (I will add i run my own company, so have the luxury of that choice) that period of 'ramp down' would let me settle into a different routine and get used to having more time.
Getting my head around what retirment actually meant put me out of kilter for a good year or so, i've always worked for myself, so always had that background worry about keeping going, but ironically when faced with that chance to stop, i re evaluated just what my work meant in terms of keeping me going.
(and definately pay for some advice - it seems painful to have to cough up, but it makes your decision making much clearer. a good advisor will map out excatly what your options are and how they change over a projected retirment timeline.)