How much time/effort required to plan?

I proposed on the 31st March 2012, we agreed a provisional date that evening (Summer Solstice this year). We weren't going to say very much until we'd booked a registry office, but Herself's sister had it all over Facebook that evening. Cue late night phone calls and emails (and convincing people who heard the next day that it wasn't an April Fool). We checked with all those we really wanted to be there and had to travel that the date was ok for them to get there. Phoned the Registrars at 9 on the Monday morning and got the exact booking we wanted.
We spent a couple of weeks looking at venue ideas, but probably less than an hour most nights, it was more chatting about what we wanted. Realised that the pub we'd met in was actually ideal, booked that. We probably didn't do anything else other than discuss what we wanted for another couple of months.
Wedding planning didn't exactly dominate our lives but we'd regularly throw ideas back and forward, some evenings were all about wedding ideas, some wouldn't have any mention of the wedding.
Because my computer logs the time I spend on projects, I can tell you that the invites took 34 hours before we had a design we were really happy with. Designing the wedding rings was 9 hours and the menu was 12 hours (I'm catering) I've no idea how many hours Herself has spent designing and making her dress (quite a few). Nearly all of that was last summer. Due to other problems wedding planning was put on hold all winter and we only managed to pick up the reins in March.
Printing and assembling the invites was probably 4 evenings (could have been done a little quicker but was fitted in while watching TV etc).
This weekend, the time spent on wedding planning related items was just under two hours, I'll spend an hour this evening on chasing a couple of things up.
I'm sure you can make wedding planning a full time occupation, but we've managed to put the wedding day together that we want, in fairly sporadic spells and lots of discussion.

For the moment, concentrate on deciding what you want and what you can afford to spend, when you know those you will have a good idea of what you need to plan.

HTH

Meanwhile, Congratulations.

I agree with Buggly - if you pretty much know what you want it's pretty easy. I took maybe 2-3 hours a week max in the busiest week, and an hour a week max in the others. It also took me no more than 8 hours to make all of my stationary, spread across a few evenings and with no help.

If it helps, we planned in 18 months but both work full time and my OH works the opposite to me - I work 9-5 Mon-Fri and he's in hospitality so works evenings and weekends. We had one evening and a Saturday max per week and EASILY had enough time to do wedding stuff and still live a normal life!

So it depends a bit on you, your OH and what you want!

We were engaged exactly 4 years on the day we got married, but only started planning & booking it 7 months earlier.

We managed to sort out venue, photographer, florist, suit hire & cake at our first wedding fair; I already had my dress (Ebay bargain ); I spent 1 whole day dress shopping with my BM; invitations were from a high street shop found by accident when looking for a birthday card; I spent about 15 hours on Ebay pulling together things like confetti cones & favours; and the longest thing to sort was my wedding ring which tookabout 6 weekends of looking to finally track down.

As others have said, it can be as easy or as complex as you want to make it