Advise on replacing toilet suite

We have 3 toilet suites that we are looking to replace.

What would be the most cost-effective way to do it (other than DIY)?

I'm thinking:
1. Buy them at Bunnings and hire a plumber to install them.
2. Go direct to a bathroom or plumbing company (Not sure if most of them do installs or not?)

How did you go about replacing yours?

 

Work out the type of pan required (not by starting with the one you want).

Check the backset
Is it P trap (rear) or S Bend (bottom)
Skew
Vented
Is it going into an existing VCP collar or pvc
Check location of water inlet (back, bottom - left/right)

Then you can start looking for a suite which matches those criteria or get your plumbing and drainage modified to suit the pan and cistern you've bought.

Hint: There are very few which go onto vcp and they've all got an exposed trap.

 

That looks like a whole lot more than what I was expecting.

After reading up on a few posts, I was expecting:
1. Measure set out
2. Check P, S or Skew trap
3. Buy toilet suite
4. Hire plumber

Another question, do we need to get a plumber to look into this before buying a toilet suite?

 

It may help - get one to come out and quote.

If he puts 10% on the toilet it'll cost you about $25-30 extra each and no risk of you getting 3 WC which don't fit.