Unless you live in Death Valley, once a month is more than enough. After a year or so you hardly need to touch anymore other than to make it look pretty and shiny. The only time I wax mine now is when I change strings, which is roughly every 4-5 months. Although They get played less now my Yamaha's have become my main basses, so strings changes will be less.
Actually, I won't be playing them in earnest for some time I reckon so I may give them a good waxing before tucking them up for hibernation.
The Warwick manual states how you should care for the neck and fretboard. It says (I think) lemon oil for the fretboard, unless it's maple which is sealed. A little goes a long way with this stuff, if it doesn't dry for a half an hour or so you've used too much. Just wipe off the excess and buff to shine, it won't damage. Also, make sure it is Lemon Oil, not LemOil, which is lemon scented alcohol. This cleans, but doesn't feed the wood.
The back of the neck should get enough oil from simply playing. Your hands should feed it all the grease and oil it needs to stop it drying out. You can use a little wax if you really want to, but there is no real need unless it gets particularly dry. I actually prefer to use a little of the Lemon oil, it seems to make for a smoother faster finish. Over time, you'll also find the neck naturally gets shinier, smoother and faster the more you play it anyway.
Roughly once a year I'll also take the strings off and give the neck a good detox. Lots of gunk and finger poo builds up along the frets and in the grain, and needs a good cleaning session to get rid of it. Well, that's debatable, some people prefer it. I use plenty of LemOil alcohol cleaning fluid to soften the gunk and the edge of a credit card or if you're careful a sharp knife and scrape it off. Then after giving the neck a good rub with the LemOil, dry it off and get some low tack sticky tape. stick strips over the wood and work right up against the frets. Needs to be low tack so that it doesn't harm the grain (or just regular tape and quickly stick it do your jeans a couple of times to remove some of the tackyness). Use some duraglit or brasso to clean up the frets and give them a good polish, wiping off excess again once you're done, then 'carefully' remove the tape. The tape serves two purposes, it protects the wood from the metal cleaner and pulls out some of the remaining dirt in the grain of the wood. Then a good dose of proper Lemon Oil, really work it in as it'll look quite dry now, and you're good to go.
One last thing, you may find in the first year of ownership at the wood climatises and settles, that you'll get get a few rough spots on the neck, and defnitely on the body. The body one's always come back for years after. Don't worry, just use some very fine steel wool or wet n dry paper on them and wax after. Will be as good as new.