Waveydavey is correct. A caution is NOT a conviction - only a Court can convict.
I speak with knowledge, as a supervisory police officer I have reprimanded/finally warned countless juveniles and given cautions to scores of adults.
A great deal depends on what is being asked. E.g. if you've a caution for D&D and you are asked if you have any convictions then the answer is no.
If the question is do you have a police record then that's different. It also depends what the caution is for. It is unusual but people can receive cautions for some very serious offences given certain circumstances.
I won't bore you all with war and peace on this. If anyone wants a definitive answer to anything, send me a message.
And on the subject of driving licence points, they are 'live' (i.e. count towards totting up) for 3 years. Less serious offences the points can be removed from the licence after 4 years, serious stuff e.g. drink drive, dangerous driving can only be removed after 10 years.