its only against guidlines if your over all width/length is past what expansion is needed for the area. If you dont leave enough expansion then you will have issues.
good, cause i do it all the time, customers love it. 8 years on the wood and laminate and never had one comeback.
Problem with wood is you cant say it has been down for 5 years or 15 years etc with no issues. If the climate changes and you have not allowed for it, well the floors will fail. I.e - we have a extra wet summer and the expanstion left was only just enough for a 'normal' summer.
Not sure I would agree with that one. Depends on the quality of T&G - again ;-) - 'cos some will already start to settle and could damage if you have to remove the lot again.