it varies from person to person
what is enough ?
owners age
car
finances
sanity
all come in to the equation
50% of the cars value is probably a good financial limit so it allows you to abandon ship for the next project
personally I would rather keep changing cars more frequent than spending a lot on one car
canb get very boring in the same car day in day out
I have rearly trough my driving years only had one car at a time
and if im honest id say some of the shitters ive owned troughout the years ive probably had the best fun in
more so than my nice cars