It would depend on several factors.....
1. subsequent applications are usually ignored/rejected out of hand if the data contained therein is nothing more than inconsequential things like COLAs (cost of living increases at work) but a major uplift due to promotion and say a better than 20~25% increase will help (but is not the be all or end all) It will be weighed and given a numerical number as is everything else in the application before it is scrutinized by "actual reasoning" as opposed to getting into the door with a magical number that is always changing depending on what the government wants to set their sights on at any given point in time.
2. As mentioned, applicant & spouse if neither are SGC, will definitely look at, again for several reasons (which ones outweigh the others is subjective for mere mortals like you and I. ICA keeps their cards VERY close to their collective chests (and I'm sure you can see the reason why just by reading a month's worth of posts on this forum). Age, if childless at say 45 probably will not get a pass. Children not included on the application probably no pass, Spouse not working as well with no children or grown children and in good health, due to age, maybe no pass but if not included also no pass. The reason for this is the aging population and the skyrocketing costs of medical care and the already straining seams of the government trying to keep medical costs affordable. Add to that, as EP holders you were not contributing to CPF, as elderly PR's you will probably not have enough your CPF to support you once you can no longer work (regardless of the huge medical subsidies received by SGC. PR had their subsidies severely curtailed probably 15 years ago. As an example an MRI is a minimum of around 1200 SGD before subsidies. for SGC that 1200 bill axes down to around net for the SGC of $300. For a PR the net costs is 900+. EP or others full cost. So if you are getting up in age, due to the stresses in the world today, You become a cost risk to the government, not a potential asset to the country. Immigration is not an open door policy, you have to show the government that you are an asset (Not to yourself but to the government - paying income taxes and buying
property is only an asset to yourself).
3. The reason children are so important is obvious. With the declining birth numbers they need a way to replenish the military AND to provide future baby ovens.
4. There are many more but a lot of this (like assimilation, for instance) are harder to quantify but the same time are, depending on a lot of related things, almost as important or can put the final star on a application. It all relevant to "what can you contribute to the NATION."
5. With regard to applications, recommended is 2 years from last rejection (not application). But without some new positively-related to items 1~4, It will appear that you are rushing and they will be wondering as this is been the normal here for the 20 years I've been on this forum and as far back as 1988 when I applied for PR the 1st time. Like a computer database, same garbage in, same garbage out. (eventually I waited 5 years and got it in 1995-still only a PR but have never applied for SGC).
Sorry for the length, but I've always been long-winded when trying to explain anything in detail.
SMS