Do you prefer to keep large amounts of inventory so as not to face any sudden problems or prefer to keep the minimum quantities?

This depend of you company industry,production industry should have plan about raw materials needed in production process,if more may affect on price i mean lost of money .but some times if keep some raw material price increase and you avoid rarely material on future.

Great question.
The reply of your question is a compound of few points: - Technical situation of your machines, and their productivity: In case they are in good condition and you are not worried from sudden break downs, then you can only keep a stock enough to meet short sales period, until the production department produce the next batch.
The calculations of production department productivity and machines capacity will determine how quick they can perform stock replenishment, and yet to advise you how long they need to produce goods, which means how long is the time you need to keep goods in your warehouse until receiving next batch, - Waste rate: in some production processes, there is a waste of raw materials happened in the beginning of machine operating or by changing from color to color.
The rate increases by reducing the quantity produced, and decreased by increasing it.
In this case: you should monitor this rate and do not let it increase due to small production orders (like plastic products industry).
- Planned sales, and products sales diagram: Sales department has to provide production department with the prospective monthly sales, and the last has to calculate the time needed to finalize the mentioned quantities.
the time between beginning with the production order and fishing it, is the time you need to keep goods in the stock.
I understand what do you wish exactly, and what you wish is exactly what all warehouse managers and sales managers wish, which is the permanent availability of goods in stock to meet any sales order, but remember that there is a well known delivery date that could be given to your customer, and also note that goods in your warehouse have value and considered as frozen money, and your finance manager will not be happy at all to see high stock in your warehouse, and will not accept that.

In General, One must maintain safety stock level beyond the safefy level you should think about the availablity of material and cost, incase of spike in demand you should able to get the material on time and important thing is to calculate the warehouse cost unnecessarily keeping the stock if no demand for past months.
 

it really depends on your business, but as a general rule you have to maintain stock levels in a way that keeps sudden or unexpected orders as to minimum, after all you have to make efficient and effective use of space available at your warehouse to receive and dispatch goods, side by side maintaing smooth circulation for outgoing orders

  The QTY kept in the WH depends on the type of the spear part.
There isn't one way to handle all materials.
e.g.
critical items that may leads to shut-down if not available, there should be enough QTY to insure the continuity of production.
On other hand, the shortage of some spear parts will not affect the production or the performance, here you can reduce the levels of stock to utilize the WH spaces and work with optimum levels with least cost.
As summary: the are a lot of parameters that will guide on who to handle some spear part, we have to consider all of them before deciding the stocking levels.
 

Inventory of an company is it's cash. To hold too much of company's cash in stock is not smart. Large amount of inventory will require large storage space, thus increasing the cost. It will also increase the risk of breakage/damage stock.

Smart thinking is to set  a minimum stock level considering the sales/production forecast of a company. 

Factors to be considered1.
Cash flow of the company:- If your company is in need of cash to meet its current obligation, day to day activities and expansion don't keep Inventories conver them in to cash.2.
Inflation:- If the country econonmic condition (Economical Statical Report) will indicate high inflation, Its better keeping Inventories to be highly profitable.
but in this case you must look / consider a.The cost benefit analysis:- Consider your future price & the cost of holding inventory.
b.
The shelf life of the product c.
The technological change, Your Customer behaviour and Competitior3.
Shortage:- If you aware that you will face Raw material shortage for certain period of time to produce the inventory its better to keep inventory to satisfy you customer need and to rise your market share and gain the advantages.
etc....

It depends on the nature of business.
You never need to stock a large amount of quantities; in other words you never need to spent money on your fear.
This is what we call forecasting.
All you need to do is to have monitor your inbound and outbound requirement.
Based on this figure you can set a re-order level or re-stock level.
In Warehousing industry we never keeps the items for long time.
Because it consume your space plus your money will remain in hold till you sell this item out.
Always keeps eye on what is your consumption and adjust your stock level according to that.
I hope this answer satisfy you.
But I am here if you required more in detail.

There are few points you need to comply with regarding what should be your strategy.1.If the cost of lost sale or non availability of certain spare parts for maintenance of your machine under breakdown is more than the the stock (inventory) including machine down time plus man hour loss or any other loss incurred due to insufficient inventory which in this case is maintenance spare parts,then it is preferred to have sufficient stock in hand.
If the inventory carrying cost and Ordering cost is more than loss of sale of finished Goods then it is preferred to have minimum stock.3.
The question you asked also relates with what type of inventory you have asked for is it Maintenance spare parts for Service industry or manufacturing industry or Trading Industry or Hotel industry.4.
Based on category of Industry,your strategy for Inventory stocking policy and replenishment policy changes.5.
We also need to focus on productive usage of finance on purchase of inventory i.e.
invested on inventory.
We need to strike a balance between Inventory carrying cost and Ordering cost and calculate EOQ (Economic Order Quantity) based on these two costs.
In a nut shell one aspect is of prime importance is that if the loss due to insufficient or non availability of required stock is more than maintaining the stock,then it is better to keep the stock.
Again there will intangible loss is there and ie.
Loss of business reputation and image in the market place if on time demand is not fulfilled for customers.

it depends on the industry ,we have to considered some aspect that can affect in our bussiness considering stocks balance availability.
if you producing huge stocks more than the needs of the consumer, it happen thiers inbalance between the supply and demand.
lost of money maybe accured in the long run.
we are keeping good quality and standard of the products when the consumer purchase the item.the good practice should be implement exact volume supply vs consumer demand.

Depends on nature of business if the turn over is more keep maintaining periodic stock levels and safty stock.
In the current busness world minimum % of inventory is ideal where you are saving huge in handling and warehousing more over less threat of pilferage and spoilage etc