You can make them last ages, you just have to look after them - I have had them last over a week before turning in to casters which I then used.
1) When you buy them, ask the tackle shop to put some ground maize (the very fine stuff) in with them. Don't bother with sawdust, it's ****. Also buy a maggot riddle apropriate to the size of a container you have. Some are metal round or square things and some fit plastic ones fit snugly in to standard size bait boxes. I prefer the latter.
2) Explain to the shop owner that you want to keep them a while and ask them to sell you some of their maize (I think I paid something like £1.50 to £3 for 1Kg which will last you AGES) or buy some from a pet store or miller.
3) When you get home (even though you just bought them) and each day, riddle them in to a clean dry container (if not bait box) and remove any dead ones (they stay limp not hard like a caster). Before I start, I tip them in to the riddle and shake it over some grass to remove the old maize.
4) If you didn't riddle them in to a bait box, clean out your bait box with kitchen paper, tip your maggies in a chuck in half a handful of fresh maize
Some random tips/thoughts...
- Longevity is all about slowing them down, keeping them cool (fridge), don't let them get wet
- Best to have more than one bait box of the right size that you can rotate. Riddle from the first in to the second and whilst they are riddling, give the first a clean out with dry kitchen roll
- Fresh maggots have a fuller stomach (brown/black blob), the fresher the better, you don't know if the tackle shop has looked after them as well as they should (despite it being in their interest!)
- Use a proper bait box with lots of little holes in for air exchange (lets fresh air in and heat out to stop them sweating)
- Make sure you give them enough air... go with half air half maggots, i.e. If you have a pint of maggots, put them in a two pint bait box
- If some turn in to casters, put them in a freezer bag and tie it reasonably tight (keep air out to stop them floating) - and boom you now have casters
- Don't forget you can also freeze maggots, dead ones make a good bait too