Ken Livingstone increased the number of buses. Boris Johnson maintained them roughly at the same level. But now we are on the verge of Sadiq Khan looking to reduce services - or in Transport for London (TfL) lingo "streamline" them.
We revealed in February that the plan was for a 7% reduction across London by 2022. What is gradually emerging is how transport bosses intend to do it.
A leaked document from TfL makes interesting reading.
The document highlights what many have been saying for some time.
Many buses in central London are running nearly empty, some less than 70% full at peak times. And bus use is falling.
The solution is to cut the kilometres buses run in central London by 9% and remove excess capacity.
TfL predicts many will switch to the Elizabeth Line when it opens.
The plan then is to "recycle" that capacity into other areas.
The issue with doing that is some existing routes will go, and some buses in outer London will now finish before they reach central London.
The concern is also the frequencies of buses will be affected. Some routes are already seeing longer waits between services.
In Greenwich the local council has concerns that shortening bus routes like the 53, 171 and 172 will impact working class communities.
And some have doubts TfL can increase passenger numbers and cut services.
Darryl Chamerlain, from local site 853london.com in Greenwich, said: "The cuts will be felt across London, but much of the impact will be in south-east London.
"Most of us don't have the Tube within walking distance, and National Rail fares are going up and up.
"If you're on a low income, of course you're going to rely on a bus to take you into work."
More detail will emerge in September. And all of the changes will be subject to public consultation.
Geoff Hobbs, director of Public Transport Service Planning, said: "Buses have a crucial role to play in boosting the number of people walking, cycling and using public transport.
"As set out in the mayor's transport strategy, we're currently looking at how we can adjust and reorganise the bus network to ensure it reflects a rapidly changing London, including planning for year-on-year increases in bus kilometres in outer London.
"We need to modernise and simplify the network and ensure that bus capacity is in the right places at the right times."
He added that any changes "will be subject to full public consultation before they're put in place."