Many of us are primarily loyal to our checking accounts, not any brand of oil.
To the extent that constant brand switching may have some detrimental effect, that can be overcome by merely loading up on a deal when you run across it.
I tend to use the same brand and type of oil in any given car over several OCIs.
If I want to try an oil, I'll wait for a deal on it and then buy enough for at least four or five oil changes.
We should also all remember that while we may have a weak consensus on the best currently available oils, the reality is ever changing as oils are reformulated either to use a basestock readily available to a blender, like Shell's GTL, to meet new performance requirements from vehicle OEMs, to make the oil less costly to produce, or for any number of other reasons.
To the extent that constant brand switching may have some detrimental effect, that can be overcome by merely loading up on a deal when you run across it.
I tend to use the same brand and type of oil in any given car over several OCIs.
If I want to try an oil, I'll wait for a deal on it and then buy enough for at least four or five oil changes.
We should also all remember that while we may have a weak consensus on the best currently available oils, the reality is ever changing as oils are reformulated either to use a basestock readily available to a blender, like Shell's GTL, to meet new performance requirements from vehicle OEMs, to make the oil less costly to produce, or for any number of other reasons.