My pump seems to have not good suction, should I buy new pump ? Or change the parts? Using spectra 9+

Is your pump still under warranty? If it is not, you can also consider sending it for servicing: http://www.spectrababy.sg/pages/terms According to their terms, for expired warranty set, the servicing fee will be $30. Additional charges are also applicable for the parts replaced. Pump parts are priced between $14 to $69.

Maybe check your valve? If you're using the original spectra valves, check for tears, cos they affect the performance alot. And the original spectra ones are so fragile. You can try changing to the medela valves. They fit my 28mm perfectly. Although they are more expensive than the spectra ones, they are more durable. :)

Maybe the flanges or nipples are not the right size? Usually if it's a suction problem usually could be those two thing. Also, you might want to check the suction, even the tiniest of hairline cracks can mess with the pressure and suction of your breast pump. If so, you can just replace the damaged parts.

Usually suction is due to the duckbill valves. They need frequent replacement from 2-4 months depending on your usage. https://shopee.sg/product/242594539/7732031072?smtt=0.0.9