Also, you may not need an accountant long term. My business is very simple. I spoke to an accountant for my first couple of tax returns, and I should probably do so again soon to check I'm still doing everything right, but the tax return is pretty simple as long as you're organised.
That depends on how much of your own research you do each year to keep yourself updated with the ever changing tax rules/allowances etc.
There've been some pretty fundamental changes over the past few years, even affecting the smallest/simplest of tax returns. For example, for property lettings the rules have changed on if/how you claim tax relief on kitchen white goods, not to mention the new rules on mortgage interest relief. For all small businesses, there's the relatively new "cash basis" and changes to the use of home allowances etc. For all businesses, the limits for capital allowances have changed several times over the past few years. Capital allowances on cars change almost every year. VAT flat rate scheme has changed detrimentally for businesses who don't buy much in the way of "goods", i.e. contractors etc. IR35 is changing again this year. Employement status seems to change almost monthly.
I've had my fair share of new clients coming to me for what they think is a simple "sanity check" of their accounts/tax returns which they've been doing for years thinking they were OK. Many times, they've been a car crash with much being wrong, not just non compliance with rule changes but also missed opportunities for tax planning/reliefs, etc.
Like I say, fine if you're affairs are simple and you keep yourself up to date with the rule/law changes, but you certainly can't just copy what happened last year without checking things havn't changed.