There are lots of things that you can do for yourself without professional help. I know how to mend a ripped seam, how to change a flat tire, and the best way to remove a splinter. I can even make my own soup when I’m sick, though I’d rather not. Sometimes, though, you just can’t (and shouldn’t) do it yourself: when your car starts making scary sounds in the middle of rush hour traffic, or when you come home to fire pouring out of every window in your house, or when it’s time to get a revocable living trust.

If you have no children, no real estate, and less than $150,000 in total assets, you don’t need a trust; you can just make a will. Even better, you can use Nolo Press (the absolute best of all legal self-help companies: to do it, and you don’t need a lawyer. But if you do have kids, or a house, you need a revocable living trust – which means you need a lawyer.

A will is a document that takes effect upon your death, and not until then. California law is fairly straightforward with respect to wills, and they’re designed to be as easy as possible for non-attorneys to draft. That’s why Nolo can provide such good “do-it-yourself” wills. Still, people make simple mistakes all the time with wills, and their estates wind up in court as a result. People notarize their wills instead of having them witnessed; they leave off the “self-proving” clause; people even choose to omit disfavored children instead of specifically disinheriting them. Any of these seemingly-minor errors, or a host of others, can result in a legal decision that no valid will exists at all.

Trusts are more complicated. A trust takes effect during your life, not afterwards. It must be funded (i.e., legally own something) to be valid, and it must be structured in such a way as to allow the trustee to do his/her job without needing to petition the court for authority or for instructions. Your trust should make the best choice of various tax scenarios for the individual situation, so that you don’t wind up giving more money to the government than necessary. Personal property should be properly assigned to the trust, and there should be sufficient safeguards in place to ensure that a funding mistake doesn’t send the entire estate into probate court. A “spendthrift provision” protects beneficiaries; similarly, the trust should allow for the possibility that a beneficiary may have special needs if he/she is disabled at the time of the inheritance. An inheritance that isn’t properly structured can do a great deal more harm than good.

Because California wills are meant to be relatively straightforward, Nolo software can handle the various scenarios without trouble. California trusts are not so designed. There’s nothing on the market that’s up to the much higher level of scrutiny and understanding that’s needed. DIY software won’t ask you if you own a gun, so it won’t know to include the required federal registration powers for your trustee. They won’t advise you that naming one of your own adult children as a trustee is fraught with the likelihood of litigation, nor that it’s better to choose a single trustee than naming multiple people to act together. And so on. Even the Nolo website says to see a lawyer “if you have a thorny estate planning issue” . . . but people often don’t know that they have a “thorny” issue. And how would they know? There’s no easy way to distinguish between run-of-the-mill issues and “thorny” ones if you don’t have a background in this area.

Got a splinter? Buy some tweezers. Need a revocable living trust? Call an attorney.