I always wear short sleeves on good grass, otherwise I always wear long sleeves. On good turf I don't find that pads matter, but on bad turf or bad grass I always wear elbow pads under my long sleeve jersey. I swear by these and they're slim enough to fit under your jersey while giving you normal range of motion:
I wear these. They are comfortable. Not a ton of protection, but I don't usually get a ton of abuse to the elbows.
Bodyprox Elbow Protection Pads 1 Pair (Large), Elbow Guard Sleeve https://www.amazon.com/dp/B072B9KB4L/ref=cm_sw_r_apan_i_5BH6W7HS26VZ1ZJP0F1H?_encoding=UTF8&psc=1
I think it totally depends on what kind of trail riding you are doing. If you're doing really technical descents with lots of rocks, I would rock both knee pads and elbow pads. In the summer when I ride more technical trails I use kneepads and they definitely have saved my knees.
This what I use for kneepads and elbow pads:
I just got these: https://www.amazon.com/dp/B072B9KB4L?psc=1&ref=ppx_yo2_dt_b_product_details as well as the same brand for knee pads. They're nice and comfortable, seem like they would offer good protection, and are low profile. The elbow pads in particular just look like I'm wearing a long-sleeved shirt or something, which is important since there are so many people, e-boarders, skaters, non-skaters, etc. that are super judgmental douchebags if they see you wearing pads of any sort.
Nice I got a similar helmet and these just for extra minimal protection without being too bulky.
Elbow sleeve: https://www.amazon.com/dp/B072B9KB4L/ref=cm_sw_r_cp_apa_i_b.iIFbXVRDBM4
Knee sleeve: https://www.amazon.com/dp/B01L379FPE/ref=cm_sw_r_cp_apa_i_O-iIFbA8DZJDF
Wrist guards: https://www.amazon.com/dp/B087M8Q887/ref=cm_sw_r_cp_apa_i_gajIFbQD9N1JA
Stay safe out there esk8rs (remember 25mph is 25mph no matter what you're riding) 🌞🌞🌞✌️