It depends on your personal goal and motivation. If you find that you want rental rather than cash out, you may want to hold for rental gains.
Yes for shophouse , commercial unit, as it get olders, it is not as easy to sell because the new buyer will have to pay upfront more cash as bank access loan through the age of the property as well.
With 74 years left, it is actually a good time to sell and the selling point includes the next owner to have a chance to sell at little profit. If you wait till 60-69years, then you may also risk capital depreciation as 5-10 yeasr time, a lot of things can happen.
Now is still a good time to sell.
Call me at 96722265 should you wish to sell.