Is it common for trades to require a deposit at time of order? Quotes for plumbing and HVAC work vary from payment at completion to 25%, 30% and even a 50% deposit!

I've been ok with a 30% deposit for window replacement as they are making the windows sized for a particular house ie they are bespoke. A 50% deposit for simple installation of drains, waterlines and fixtures doesn't seem reasonable to me anyway? Stage payments would also be ok but a 50% deposit is probably a non-starter.

All the plumbers seem to want to install PEX piping instead of copper lines. I suppose the material is cheaper and it's faster to install. Someone told me that PEX isn't approved for residential use in all provinces and it isn't approved for use in commercial applications - is that the case?

All our trades are paid on account. However, we have been dealing with them for a long time and they make a good living off of us. Often a trade has to buy supplies, some folks hire a trade and never pay (so I have been told). The best trades people can pretty much demand what they like, especially when work is plentiful.

Out trades have so much work, they choose who they work for and who they don't.

Pex pipe is in common use with the price of copper now. I feel sure if you insist on copper they will supply it, but expect to pay. We have a lot of it in various locations.

I think I prefer pex piping anyway - suspect it might be less likely to split if the heating fails and the basement freezes! Our tradespeople have never asked for a deposit for anything.

I did ask the plumbers to provide a price for copper piping as an option over the PEX. Some did this quite readily and others were more reluctant. For the time we'll be in the house PEX is probably ok. Whether a buyer in the future would be interested or unhappy with the house having some PEX piping who knows?

An acquaintance who paid a deposit to a trade for some work on their house said they would never ever do that again. The trade never turned up when they were meant to, didn't progress the work etc.

It's not and it has a shorter expected life than copper. For most that is likley not an issue. When used in exposed situations, sunlight degrades it too.

Several websites say that Pex IS more resistant to frost than is copper - e.g., Frequently Asked Questions / Apollo Flow or Easier Plumbing with PEX Piping - DIY - MOTHER EARTH NEWS . I have not found any which say that copper is superior.

One might like to look up the various lawsuits concerning Pex piping....

To return to the OP's original question: a 10% deposit seems reasonable to me, depending on the magnitude of the job to be done. Anything more than that I'd be wary.

[aside: I wouldn't use pex myself].

It really depends on what is being done.

Trades are trades and not banks. You should not expect them to finance your project. For example, if you want a new furnace installed then it is not unreasonable to pay for the furnace up front and the installation labour on completion.

As Aviator says above, good trades will have all the work they need so why should they risk their income on a homeowner who may not pay for the work done. Putting a builder's lien on a residence is a pain in the rear. If a customer will not pay a reasonable deposit then they can work for someone who will.

The above said, I would not expect to pay much more than a token deposit if a job was just a few days labour work.

I think it is better to choose your trades by recommendation rather than their payment terms.