Advice on bridge/implant.

How much does smoking negatively impact implants long term and what are some complications with a bridge? I've heard people complain about food and keeping the space under the bridge clean is difficult, how true is this?

I'll be having a root canal and crown done on #28 in the next month and would eventually like an implant put in and bridge to fill in my missing molars (31-29). Would it be best to have an implant at both ends of the bridge or can I have one implant around #30 and bridge it to the crown at #28?

I'm healthy besides my teeth (I do have week enamel) I lost my molars due to neglect as a child and then snowballing of fear of the dentist. Luckily with the support of my spouse and a very nice dentist I'm getting back on track. I'm only in my early 30's so bone loss is a concern of mine.