The sole purpose of a probate seems to be to assure the holder of assets of the deceased that the will is the genuine last will and that the excutor is the real person ... and to provide the government with probate fees

... the executors have the authority to deal with the assets under a will without getting probate, but financial institutions and transfer agents for public company securities will often not release assets without the comfort of knowing that the court has confirmed the authenticity of the will and the authority of its executors (in other words, probate).

Probate is generally necessary in cases when:

• a bank, trust company or other financial institution insists on the will being probated to prove that the executor has the authority to act.
• the assets include shares owned in a private company.
• the executor needs to sue an individual owing the estate money.
• there are creditors due money from the estate.
• a will's terminology is unclear, ambiguous or certain provisions are not stated. (For example, if there is no provision to pass assets to another heir where a spouse has predeceased you).
• a will is improperly witnessed.

It says here:

Marie Sarah Eurig, the executor of her late husband's estate will receive back the $5,710 in probate fees. She paid the fee to settle the estate, and went on to the Supreme Court. Pushing the case was Mrs. Eurig's small-town lawyer, from Durham, Ontario who apparently took the case for free to prove that probate fees were illegal ... A farmer's widow and a small-town lawyer took probate fees to the Supreme Court and won!

As you'd expect, the government would like to have its probate fees. The Ontario government says here

The estate trustee's duties include:

• making funeral arrangements in accordance with family wishes
• locating the original of the last will
• applying for probate
• gathering assets and arrange payments of debts including income tax.
• filing tax returns for any untaxed years
• should obtain a clearance certificate from Revenue Canada that taxes are paid
• arrange for distribution and sales of assets
• there should be no distribution of assets in the first six months without court authorization or permission of the spouse since dependents have 6 months to contest a will. The distribution of the assets may also be subject to claims under the Family Law Act.

Probate -- is when a will is proven valid or authenticated in court. It confirms that the will is the deceased's and that it is the last will. It also verifies the appointment of the person named in the will as executor.
The probate fee in Ontario is assessed on the value of the estate at a rate of $5 per $1,000 value of the estate on the first $50,000 and $15 per $1,000 thereafter. An estate of $250,000 could result in probate fees of $3,250.

Probate fees are payable to obtain a Grant of Letters Probate (or, if there is no will, Letters of Administration). Letters Probate means the court has confirmed the validity of a will and the authority of the executor of the will. An executor's authority, however, comes from the will and not the Letters Probate.

About Power of Attorney
It says here (among other things):

• 2. Are there different kinds of Power of Attorney?
  Yes. In Ontario there are three kinds of Power of Attorney:
  • A Continuing Power of Attorney for Property covers your financial affairs and allows the person you name to act for you even if you become mentally incapable.
  • A Power of Attorney for Personal Care covers your personal decisions, such as housing and health care.
  • A non-continuing Power of Attorney for Property covers your financial affairs but can't be used if you become mentally incapable. You might give this Power of Attorney, for example, if you need someone to look after your financial transactions while you're away from home for an extended period of time.

• 21. Do I have to use a specific form to make my Continuing Power of Attorney for Property (CPOA)?
  No. A special form is not required. But to be valid, the document must:
  • Be called a Continuing Power of Attorney for Property or say that it allows your "attorney" to continue acting for you if you become mentally incapable.
  • Name one or more persons to act as your attorney for property.
  • Be signed by you and dated.
  • Be signed by two witnesses who saw you sign the document.

• 37. What powers will my attorney have?
  Unless you restrict your attorney's powers, he or she will be able to do almost anything that you can do concerning your finances. Your attorney can sign documents, start or defend a lawsuit, sell property, make investments and purchase things for you. Your attorney cannot, however, make a Will or give a new CPOA on your behalf.

• A living will (or "advance directive" or "personal directive" or "representation agreement" or "power of attorney for personal care" etc. ... depending upon the province) is a document containing your wishes about your future health or personal care.
• You make a living will when you are capable of understanding treatment choices and their consequences and it takes effect when you are no longer capable of understanding treatment choices and their consequences.
• Your living will should have a Proxy Directive specifying who (the "proxy" or "agent") should make decisions on your behalf (when you are no longer capable).
• It should also have an Instructive Directive specifying what health care or personal care choices you want your proxy to make.
• A living will may not have an Instructive Directive but should, at least, name a person (or persons) to make health care decisions when you are no longer able.
• A living will is similar to a "Continuing Power of Attorney for Property", but deals only with health care (and not finances) and, indeed, is called a "Power of Attorney for Personal Care" in Ontario.
• Your living will should be witnessed and signed by adults ... but NOT the proxy or spouse or children.
• Copies of your witnessed living will should be given to your proxy (and maybe your doctor, lawyer, relatives etc.) so that those involved know of your wishes.

See: Ontario Govt. and Univ of Toronto Centre for Bioethics Living and Living Wills.

A "typical" living will (for Ontario, at least) is shown here