firstly sorry for such a lame question!
I have gone through a number of base layers the past year and had to bin them to being stinky!
I wash them after every ride, or there and back if commuting to work. I use Nikwax base fresh every now and then with all my base layers together.
They are still often pongy however...!
I have had a few DHB merino ones... a couple of fox polyester type ones..endura baa baas...
Am I wearing the wrong bases? Missing a trick when washing? Or just too sweaty...? Any tips?