Using "I" or "we" to refer to sole proprietorship?

I have a company which consists of only myself. The company has its own distinct name which is registered.

Should I use "I" or "we" to refer to my own sole proprietorship when writing marketing materials, introductions, offers, etc? If both are generally acceptable, what sort of different nuances these writing styles convey?

For example:

• We provide the following services: blah, blah, blah.
• I provide the following services: blah, blah, blah.

I am hesitating to use "we" because I am afraid that it will look like I am trying to make my sole proprietorship seem like a bigger company.

I am hesitating to use "I" because it would be silly to re-write everything if I ever hire someone or get a business partner one day.

You should use "we" when referring to the company or speaking for it. Technically and literally, a company implies more than one person. Many countries allow one-person proprietorships by simply bending this definition by allowing the director to also masquerade as the required shareholder.

In any event, people expect companies to involve more than one person and might be thrown off a little by the first-person singular. I suppose an exception could be made if the company is named something along the lines of John Doe Services, where you are said John of Doe.

There's no law saying you can't use we for one person - even the Queen does it!

It would be normal to use we for a company, even if there was only one person doing the job.

It's also standard for scientific papers: "We present a possible solution to the problem of blah...."

You and the corporation are not the same entity, you have different responsibilities and liabilities, different lifespans, etc.

We is appropriate, and as David Wallace said in a comment, you don't want to throw out all of your marketing material just as it starts paying off because I is no longer accurate.