The first thing you should do is make sure that each estimate talks about the same work! If you gave clear specifications then each estimate should list the same work. If not, ask why.

If you didn't give detailed specifications then there are likely a lot of differences between estimates. Such differences are not necessarily bad. Just be sure to account for those differences when comparing the estimates.

Always be cautious around low bids!

There may be many reasons a bid is significantly lower than the others. For example:

• The bidder may have other jobs in the area they can combine to save costs
• They may be offering a discount to keep thier employees working during a slow period.
• They may be willing to take a loss to give them the opportunty to establish their reputation with you and your neighbors.

The reasons may also be they:

• don't carry liability or workers compensation insurance
• don't pay thier employees' Social Security or Medicare taxes
• hire illegals
• cut corners on safety
• aren't qualified, trained or skilled in tree work

If you are considering hiring the lowest bidder don't be afraid to ask some serious questions. Ask them for

• references
• a current copy of thier Certificate of Insurance issued by their agent. Don't accept a copy they hand to you. Only one sent to you by their insurance agent is valid!