Our family is in the enviable position of being on the almost-finished side of a large addition and interior renovation. And, overall, the reno was an incredible adventure for the family — one that we had dreamed about for years. We ended up with a gorgeous house that fits us like a glove. What could be better?

Well, getting there was not always as smooth as we wished. The process was actually fun most of the time, but in the final analysis, we realized some of our mistakes ended up costing us a lot of extra cash.

In a nutshell, most of our mistakes were largely the result of not planning enough. For those of you contemplating doing a reno, here is our advice, straight from the school of hard knocks.

>> Make changes during the planning stage, not the construction stage. Paul Catania of Verly Construction, the head of the company that managed our renovation, puts it plainly: “If it’s well-planned, and you work through the model at an early stage, you’re set. Four months of doing that would have saved six months of work later on.”

>> Our architect, Tony D’Andrea of Torplan Consultants Inc., agrees. “One of the biggest problems is that people don’t give themselves enough time — give yourself at least six months for planning, and six to eight months for construction.” He emphasizes the planning must be thorough — including reviewing every aspect of the plan, city permit requirements, parking issues, and a myriad other details.

>> In our case, one of the things we did wrong was hire an interior designer after drywall walls and ceilings were already in place. “It’s a lot easier when you make changes before the drywall goes up,” notes our on-site contractor Joe Rego, owner of Rego Contracting.

>> Make decisions about precisely which fixtures and furniture you will buy as early as you can because the exact measurements of these items will dictate where switches, outlets and plumbing will be placed. Lina Pelaez, our construction co-ordinator from Verly Construction, notes wryly these types of decisions should be made before she calls in the trades.

>> Be realistic. If you are combining old and new parts of a house during a renovation, budget for uniformity. Don’t leave the old part as is, alongside a completely new renovation.

>> Our assumptions that we would stay in the house for the duration of the renovation became ridiculous once renovation started in the old part. Rego sums it up succinctly: “With a large reno, move out. That way the contractor has the opportunity to work everywhere, inside and out.”

>> He also advises the construction site be emptied for a large project. Ours wasn’t. “Freedom of movement makes a big difference in construction — it takes triple the time to move stuff up and down the stairs, and back again, and things are missed” when furniture is piled up along a wall. (Sorry about that, Joe.)

>> Learn from your mistakes — you never know when you’ll get the reno bug again.