OpenWrt is often ideal for older or cheaper modems to provide lots of extra, and up to date, features and security patches - Check when you buy, that a modem is OpenWrt compatible
Danie van der Merwe · news.movim.eu / gadgeteerza-tech-blog · 10:23
It's a fact of life that most proprietary vendors only support their hardware for a few years with updates. Another practice is selling their cheaper modems with a lot of functionality missing, to encourage buyers to pay up for a more expensive model to for example get mesh networking, load balancing, real-time network monitoring stats, etc.
So it's worth always checking, when buying a new modem, if it is OpenWrt compatible, as this will allow you to reflash the modem with OpenWrt. It could also mean buying a cheaper modem now, and gaining some extra functionality at no extra cost. But most important is that you can continue to get software updates and security patches.