Question: My kitchen has been built with bricks, but external rendering has not been placed. Now it has been 17 years but nothing has happened, but I want to know if I need to externally render the wall? Could anything have happened to the brick wall since the rainy whether?

Answer: 
No, brick & its mortar will be fine for 100-years in the weather. You can absolutely Stucco it as well & that will last almost the same amount of time. But, unless the Stucco would be done to match the rest of the exterior, then don't bother. It's just another potential future problem.

However, you can treat the brickwork with a clear Masonry Sealer, only if the brick appears to be wet a day after being rained upon. I say that because the sealer would need to be re-painted every 5-years & you really don't want to add that constant maintenance unless & until you need to.
NO u dont have to plaster the wall.You can get sealer for brick and block. You can get this at home depot or lowes.If you prefer to plaster ask the person at the hardware store for plaster wire it comes in 4ft by 6ft sheets .Screw it to the brick wall .In the mortor joints.and plaster away.thank you .Master Mason.Harlan