Bus never comes at time stated

On multiple occasions over the last few years the 118 does not stop at the bus at the time stated on either the bus shelter or the live bus arrivals page on the website. Too many times the 118 bus is either arriving more than 5 mins early or 5 mins later than stated. On many occasions the 118 bus will say its arriving in 20 minutes and then 2 busses will arrive together 10 minutes later, and then nothing will come after the full 20 minutes. I live several yards from the bus stop and try to time my leaving the house with the bus arriving and despite leaving many minutes earlier and keeping an eye, refreshing the live bus arrivals, I find my myself running and missing the bus that arrives at whatever time it feels like. It makes it incredibly difficult to navigate getting to work or utilise the various transport services. What is the point of having this technology if it is consistently inaccurate. Myself and many other users have abandoned using tfl, especially this route because of this.