The 'best' time to sell is when it is convenient, necessary or 'no alternative'.
Currently, the interest rate is the lowest it has been for decades ( and I've been in the business and have seen 17%) a few decades ago. Listening to friends , relatives and financial advisers is a good idea, but following the advise requires your needs. The market goes up and down - for the past few years it had reflected in values rising 5 -6% a year in some areas - it might float down at the rate too. Too many variables to really predict. The unemployment rate: the interest rate, the arrival of a new business or loss of a business in an area - the intrinsic aspects of a particular community. ( we have sidewalks, parks, neighborhood shops, over 200 civic, volunteer, historic and service organizations) are near Montclair State University), train to mid-town NY,( direct ) and a bus line too and 20 minutes from Newark Airport) Do they make a difference? What do you think?
If you are behind in mortgage payments - foreclosure is possible, but a short sale would be less 'negative' on your credit for future needs. Bankruptcy should be the last alternative. To sell, ( hope to get the debt dismissed, )or you are still on the 'hook' for the difference in the mortgage owed and the amount received at the sale.
We are a credit based economy - from restaurant dining, to internet purchases, to auto leases etc - start using cash - or not spend if a house debt is too big. Try to have the mortgage you have restructured - rent a room to a student - read all that is available - make your own decisions,