i picked up bulbs for tulips, hyacinth, crocus 2-3 months ago. how long will they last before i need to plant them in the ground?
The bulbs will be still viable, but it is very important to plant them out as soon as you can.
A lot depends on the conditions under which you are holding them. If you have them in a cool and moderately humid environment then they could hold for a little while longer.
If you have them in a warm place with low humidity then they will start to dehydrate. One consequence is that the flower bud which has already formed within the bulb will become withered as it doesn't have the resilience of the more starchy parts of the bulb. Yes, it may come up, but all you will get this season (usually) will be leaves and a less-than-best flower display (if the season is kind.)
When you touch the bulbs - are they 'rubbery' or still firm? The 'rubbery' ones need to be planted into a free-draining mix and not at 'normal' depth, IME. Much closer to the surface - as if you were doing a multi-layer planting for a sustained display.
Flowering or not - allow the plants to finish their full cycle - all the way to brown and withered leaves before lifting them and storing them over the summer.
If you can, plant them out in spring, directly from the container, with minimal root disturbance, so they can grow on.
A touch of tomato fertiliser mixed with the soil or potting mix will help develop healthy bulbs and, hopefully, flowers for the next flowering season. It can also improve disease resistance.