My wife and I are going to open a business this coming year, can we deduct what we have already spent in equipment, or do we wait until its officially a business (2018)

You will wait until you place the items into service which will be in 2018 no matter when you bought them.

Technically, we will be using them now. Graphic design for wedding invites, custom cards, so we will be using the computers now to build "stock" for display on the website we have yet to build, Etsy, Facebook and the like, but if I read that right, I can just wait til 2018 when we are actually a business and advertising before I claim them as in service?

You can't take an expense until you start having income.  Once you start having income (2028), some of your startup expenses can be deducted and the rest are amortized over 15 years.  And of course, computers and other durable assets are subject to depreciation rules and may not be immediately deductible.

Since "we" will be starting a business make sure to get the Partnership or Corporation set up correctly ... seek out professional guidance to get this done correctly for your state.

Your reference to "my wife and I" indicate that this business will not be a sole proprietorship, independent contractor or single member LLC. For any of those three, all business income/expenses is reported on SCH C as a part of your personal tax return, including a joint return filed by a married couple.

Therefore your business will be either a multimember LLC, partnership, S-Corp or C-Corp. For these business models the business is considered to be a separately taxable entity and the business will file it's own physically separate tax return. Additionally, when the business files it's tax return, it will issue the appropriate tax reporting documents (K-1's, W-2's, etc) to each owner/shareholder in the business. So the recipient of such tax documents issued by the business can't even start their personal return until after they have completed and filed the business return.

When it comes to taxes, the rules for a business structure with more than one owner vary from state to state. Remember, you register your business at the state level, while that business will file a yearly tax return at the federal level. If your state taxes personal income, then the business must also file a tax return.

Even in states that do not tax personal income (such as Florida) the business may still be required to file a state return, and possibly be required to file more documents with the state multiple times during the tax year.

As you can see, things "can" get complicated rather quickly. You're doing the smart thing by asking questions before you find yourselves in tax hell. It is not uncommon for a business to go bankrupt before it even gets off the ground, because the business owner(s) were not knowleable on the tax filing requirements at both state and federal level, and other filing requirements that you as an owner may be required to file quarterly by law with the state, as well as with the federal government in many cases. When it catches up to you (usually towards the end of the 2nd year of business) the back taxes, late fees, fines, penalties and interest imposed can quite easily (and very often does) bankrupt a business before it's even off the ground. For example, "failure to file" penalties can be as much as $200 a month for each month you are late, and for each item you are late filing.

Now I'm not trying to scare you here. I'm trying to point out the importance of seeking PROFESSIONAL HELP for your startup time and first year of business on the tax front. If you don't, and you do things wrong, the cost of trying it yourself and messing up can quite easily (and almost always does) make the cost of a Tax Attorney or CPA seem like a pittance in comparison.

In the process of seeking professional help, look for a Tax Attorney or CPA with what I call the "heart of a teacher". If they're any good, they will teach you about this tax stuff so that you are doing things in accordance with the tax laws of your specific state. Then after that first year, you can if you want (and probably will be able to) do all your business related taxes and other filings on your own, using a program such as TurboTax.

Basically, if the Tax Attorney or CPA wants to keep the details of your business tax requirements a "secret", they're in it solely for the money. You are paying them not only for their services, but also for their knowledge as it relates directly to your specific needs. So if they're not willing to share the knowledge, don't hire them.

As a side note, when starting any business venture you'll have what is referred to as "startup costs". These are costs incurred before the business is "Open for business" and those costs are specifically and explicitely "for" the business. Startup costs are claimed as such in the tax year the business is "open for business". It does not matter in what tax year those costs were incurred either. (It's not uncommon for a business to have 3 years of startup costs incurred prior to opening for business.)

Generally, startup costs are not "deducted" per-se. They are instead capitalized and amortized over the first 15 years of the business.

Oh, it's also imperative that you keep all receipts and maintain detailed documentation of all startup costs incurred. When dealing with the IRS and state tax agencies, if it's not in writing, then it flat out did not occur.

ok, I used the phrase "We" becasue as her husband, I am free labor and sounding board LOL. To be precise, She is starting her own business, I am simply the indentured servant. As far as the rest of it, that precisely jives with what I have found to be true by speaking to others whom also own their own businesses. As this becomes more and more real, you can guarantee that at least for the first year or two a professional will be involved. Thank you so very much.

For a sole proprietorship or single member LLC which is reported on SCH C of your personal tax return (including a joint return) you don't file the SCH C or report anything, until the first tax year the business is open for business. While I still recommend seeking professional services if you've not got the experience and/or knowledge in this, make sure the person you pay for their services teaches you, and doesn't just "do" it for you without you knowing the intricate details of what's going on when it comes to taxes. If they're not willing to share their knowledge, then why pay for it.
For a SCH C business, all expenses incurred prior to the official open for business date, are called startup expenses. For most many of these expenses are not deducted per-se. Instead they are amortized over the first 15 years of the business. Some expenses may actually be business assets. Those are capitalized and depreciated over time. What gets amortized and what gets capitalized depends on the nature and type of startup expense.

Up to $5000 of start up expenses can be expensed on the first year you have income to report.   If your start up costs are more, then part can be expensed and the rest has to be spread out over 15 years.