Well it depends on the bars, you, and how long they have been used. Ive been riding my bars for 3 months and i check them occasionally to see any changes, but other than scratches, its all the same. So that shouldn't worry you. Are you a big person or small? If you're big, you tend to land harder and that might cause bars to bend faster. And lastly, what bars are they? If they are some Metal2metal ----- they will bend pretty fast, but if you're getting crows or slaYers then don't worry about it.
good luck dude.