Continue to check outlet voltage at different times of the year to get a truer picture of voltage reliability since some changes may prove to be seasonal...if you typically have icy conditions where you live it may be the worst during the winter months.
If your voltage proves to be fairly regular, you're probably lucky. When considering voltage regulators, audio components are spec'd to operate within 5% of 120v. They all are equipped with (necessarily fixed) noise cancellation circuits in the power supply that deal with 60hz noise and all its multiples - 120, 240, 480, etc. But, the closer you get to the edge of that 5% window (and beyond), the more noise will slip past the cancellation circuits and affect the sound...that general malaise that tells you it's feeling kinda sick (and not in a good way). This is why people feel like regenerators reduce noise, they don't per se, but they can keep power supplies operating at or very close to spec. But...if it turns out you truly don't often have much of a voltage problem, then you could likely spend that money elsewhere...like balanced power, usually excellent for everything but your amps (unless you're talking about a Huge transformer). A good rule of thumb is that the capacity of the transformer needs to be at least about 40% over the value of all the power supplies that will be used with it. But, typically, they are a major step forward in sound quality. A First Watt shouldn't pose too big a problem.
If your voltage proves to be fairly regular, you're probably lucky. When considering voltage regulators, audio components are spec'd to operate within 5% of 120v. They all are equipped with (necessarily fixed) noise cancellation circuits in the power supply that deal with 60hz noise and all its multiples - 120, 240, 480, etc. But, the closer you get to the edge of that 5% window (and beyond), the more noise will slip past the cancellation circuits and affect the sound...that general malaise that tells you it's feeling kinda sick (and not in a good way). This is why people feel like regenerators reduce noise, they don't per se, but they can keep power supplies operating at or very close to spec. But...if it turns out you truly don't often have much of a voltage problem, then you could likely spend that money elsewhere...like balanced power, usually excellent for everything but your amps (unless you're talking about a Huge transformer). A good rule of thumb is that the capacity of the transformer needs to be at least about 40% over the value of all the power supplies that will be used with it. But, typically, they are a major step forward in sound quality. A First Watt shouldn't pose too big a problem.