Value of Bathroom Remodel?

[Jenny Milu]

My husband and I are currently trying to decide if upgrading our master bathroom is worth the investment or not?  Currently we have ample storage space, a double vanity, a toilet (crammed into a small area) and a very small shower in the master bath, to expand the bathroom and upgrade the shower ( knowing it's quite a bit of construction) we are looking at a ball park of ~$40k is there a way to know that this investment will hold when it comes time to sell the property? The home is a bit older, built in 1964 and who knows what we are going to find in the walls when we open them up!