Struts degrade very gradually often it's hard to notice. Mileage alone is not a good indication, but in general by 50K miles most of the damping on these budget struts are gone. So I agree with Monroe, Gabriel, and KYB (Toyota OEM, aka "K
) about that 50K mile figure. Of course, the excellent Bilsteins are supposed to be good over 100K miles. I believe that too. So 183K miles is most likely, but not to say your struts are to the point of needing immediate replacement.
Besides a second opinion from a reputable shop, I would check the Monroe FAQs. http://www.monroe.com/support/faq.asp
For example, read the Q&As about the topics we have mentioned:
"How many miles do shocks and struts last?"
"How do I know when my shocks or struts need to be replaced?"
"What will happen if I don't replace worn shocks or struts?"
"Are there any other parts I should consider replacing while having my struts / shocks serviced?"
The QuickStruts will give you all new components but at a higher cost (not that much if you ask me). If cost is your concern then at least do the strut and the mount. You can take a peek to see if there are cracks or dry rot on the rubber bellow and insulator. I'd go with all new components and the easy to install assembly.