why in this day and age do routers still get slow over time?

[kofman13]

I have a decent ASUS rt-AC56R dual band router i got in 2017(maybe early 2018)? In an ideal situation i get the full 150 mbps download on wifi as i do on ethernet. 100% of what i pay for. but always after a month or so, or even several weeks, it starts to get really slow to the point where on ethernet and wifi both are getting about 20-30mbps. a power cycle SOMETIMES fixes it but usually not. Then ill factory reset and most of the time it will give me the 150mbps speed again for several weeks or a month and then starts slowing down again. This has happened the exact same way with the last 3 or 4 routers in the years before this current asus one. after 1-3 years they just start getting slow and acting wonky. i cant be the only one who just cant get a router to perform well for over 1-2 years. luckily they arent expensive to replace/upgrade every year or so, and the few ones on sale for prime today are tempting me right now.

on a side note, i noticed my router is really hot, but i dont know if it was less hot in the past.

[ben_zen]

Routers are often not the best from a software perspective, and they can often fail to clean up logs and caches-especially caches. If you're seeing lots of issues with speed, try forcing your router to drop its ARP table; if that's got stale or wrong entries, the router might be trying to send traffic to the wrong locations or use slow paths. It looks like the manual doesn't really provide options for this, so doing a full reset may be the only real option.