I have been building for years and look for any material to use, whether its old or new, but I like recycling because it stretches my dollar and saves things being tipped.
Of late I realised
pallets come in different sizes and the longer ones often provide nice bits which can be used as strapping over plaster sheet joins, architraves, moulding around doors, windows frames etc.
I don't machine it, but it does make good mouldings if you don't like the rough finish.
I sometimes leave it raw, or undercoat and paint it what ever colour I have in mind.
It saves a lot of money, looks good if thats what floats your boat as they say.
Where I live in Bendigo, Australia, there is even a bloke who dismantles pallets and sells the lengths separately.
I collect my own and spend the time pulling them apart.
There is a good tool which firs a pin through the
wood and punches out the nails.
Its easier than the alternative, but I have made useful levers and wedges which also help pull the pallets apart without damaging too much of the timber.