We strongly advise that you personalise the colour of each of the NetSuite environments that you have access to, so that they are instantly recognisable.
The recommended colour coding is as follows;
SandBox 1 = RED
SandBox 2 = ORANGE
Production = BLACK
To change the colour of the environments (as sadly this can't currently be controlled centrally for all), please follow these steps;
Click on the Home button, then Set Preferences
Select Appearance, then select the Classic Colour Theme as per above recommendation.
Then click Save.
Your NetSuite environments should then look like this;
PRODUCTION
SANDBOX 1
SANDBOX 2