Probate is the legal process through which the court sees that, when you die, your debts are paid and your assets are distributed according to your will. If you don't have a valid will, your assets are distributed according to state law.
Probate is a public process, so any "interested party" can see what you owned, whom you owed, who will receive your assets and when they will receive them. The process "invites" disgruntled heirs to contest your will and can expose your family to unscrupulous people and people that are just plain nosey.
Is probate expensive?
Depending on the situation and the state law involved, probate can be relatively no big deal or it can be expensive.  Legal fees, executor fees and other costs must be paid before your assets can be fully distributed to your heirs.  If you own property in multiple states, your family could face multiple probates, one in each state in which real property is owned. Because these costs can vary widely from state to state, be sure to get an estimate.
New Mexico has an informal probate procedure that can be utilized that is very inexpensive and can usually be completed in three to six months. There is no statutory fee in New Mexico which means that the fees are based on the time involved in completing the probate. Most uncontested probates in which the assets of the estate are located entirely in New Mexico can be handled by an attorney for fees ranging between $2,000 to $4,000.  By way of comparison, we are advised that the average probate in California may take 1 to 2 years to complete and the attorney fees are often in the $10,000 to 30,000 range or higher.