It depends yes. Reason is because if you try on or put on new clothes before washing them you never know if the person before who tried on those pants might have had a sickness. So I always wash my new clothes when I get home. Also no. Reason is that some of the jeans might have a different kind of texture/fabric that it might be itchy on you sometimes. So you should see what kind of fabric the jeans might be.
I never did until I saw a documentary. They have travelled far and wide to many dirty places before they arrive in stores. Steaming decreases and presses the jeans but does not eliminate dirt and dyes. To prevent rashes and or infections I now recommend washing before wearing.
i wash all my new clothes cz i don't like knowing that someone else has been in them b4 i bought them i recommend washing simply cz u never know who was in them before u and could give you what they had .