Hi Ilovetoffeenutfrapp!
Retainers do undergo wear and tear with time, it depends on the individual case, as some people grind more than others and different retainer materials would have different results as well.
With the advances in digital dentistry, some dentists and orthodontists now have intraoral scanners and software systems, which are able to predictably and accurately align your teeth using their own in-house custom clear aligners. For minor misalignment, this would work great for you, and the cost should not exceed a few hundred dollars if only 2-3 aligners are required. Of course it would require a proper clinical assessment, if it requires more than 5-6 aligners I would strongly recommend Invisalign.
I would also advise bringing your current retainers along for the consultation visit so that the dentist is able to ascertain why they have cracked or loosened with time. If you grind at night, a stronger retainer material or even a night splint should be planned as part of the treatment plan at the end of alignment to ensure your teeth do no misalign again.
Hope this helps, all the best!
Warm regards,
