I cant see myself w/c at 50 simply because it is a physically challenging job to do all day long.
If your worried about taking the plunge and need a security blanket just do it P/T or weekends for a while. I still work part-time in a sales job I love - this keeps me happy and covers the morgage if we get prolonged periods of bad weather.
The real benefit to me is the flexibility of the working week. I really love taking and picking up my daughter, I attend every school function but from a work perspective its all about maintaining a regular cleaning cycle. Two hands are better than one I suppose. It takes the pressure off hubby and thats a good thing. Also we have picked up new accounts because the elderly feel more comfortable seeing a woman.
Its a physically demanding job but mentally its a doddle - you dont have the stress of an office based job and can go home and forget about what you have left at the office.
The Work - life ratio does it for me but I suppose its all down to your personal situation and what you want out of your work (or not as the case may be)
Hope that helps ,
Sarah