2 critical things for e-commerce: Compliance & Quality
When selling on an e-commerce platform like Amazon for example, the 2 most critical things to concern yourself about are Compliance and Quality.
Compliance: I need to make sure my products are Legal to Sell
Quality: I need to make sure I am selling good quality products
Why?
Compliance:
If the products are not legal, they will be delisted and possibly destroyed and you lose your investment
Your permission to sell anything on the platform may be revoked
Quality
If the products are bad quality you will get returns = higher costs/loss of sale
Bad quality leads to bad reveiws, which lower your ability to sell future products
How to avoid these isses?
Compliance
Test your products for regulatory compliance at a QIMA Lab
Quality
Make sure you have a product inspection program in place on every product you source

Most people that are selling on marketplaces like Amazon source products from Asia or any country/region and never see the products, since those are shipped straight to Amazon warehouses. Therefore, quality and compliance play a critical role and it is a recommended best practice to increase the success of your online business.