I use a standard charger and an Oxford Products Optimate trickle charger. I find the trickle fine for the journey's I do, in and out of town, 3 miles. I rotate the trickle onto each of my 4 batteries every 24 hours to keep them all 'alive'. If I have a big trip to do I use the standard charger for 12 to 16 hours if I have any doubt about them. By the way I bought my Oxford Product Optimiser for my Fireblade, back in the day(!), it is only supposed to work for upto 30 - 40 ish Amp hour batteries but it works fine on my (upto) 80 A/hr batteries....
I think it is good to keep batteries receiving charge, I think it extends the life of the battery.
I guess for your use it would depend on how far your commute is? If it is less than 6 miles return using a trickle should be OK. Try it out and take a spare if you are not 100% confident.
As it happens Connie and I did a long ride at the weekend (lovely and sunny in Stratford), my 60A/hr battery did 15 (fairly flat) miles without much pedaling before it gave out and I swapped the battery to the spare I was carrying.
If you wnat to 'fix' a knackered battery you need a C TEK charger/conditioner/repairer. Really excellent products, read the interweb about them. We use them at work and they do a very good job. They are more expensive than a simple Optimiser like mine at home but I think they are a more sophisticated range of products.
Cheers, Giles